diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index ea67cf2..95579da 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -370,8 +370,7 @@
   add_library(test_util
               evaluator_test_utils.cc
               numeric_diff_test_utils.cc
-              test_util.cc
-              codegen/test_utils.cc)
+              test_util.cc)
   target_include_directories(test_util PUBLIC ${Ceres_SOURCE_DIR}/internal)
 
   if (MINIGLOG)
@@ -527,6 +526,3 @@
   add_subdirectory(autodiff_benchmarks)
 endif (BUILD_BENCHMARKS)
 
-if(CODE_GENERATION)
-  add_subdirectory(codegen)
-endif()
diff --git a/internal/ceres/autodiff_benchmarks/autodiff_benchmarks.cc b/internal/ceres/autodiff_benchmarks/autodiff_benchmarks.cc
index cf2d558..3d1699b 100644
--- a/internal/ceres/autodiff_benchmarks/autodiff_benchmarks.cc
+++ b/internal/ceres/autodiff_benchmarks/autodiff_benchmarks.cc
@@ -39,10 +39,33 @@
 #include "ceres/autodiff_benchmarks/relative_pose_error.h"
 #include "ceres/autodiff_benchmarks/snavely_reprojection_error.h"
 #include "ceres/ceres.h"
-#include "ceres/codegen/test_utils.h"
 
 namespace ceres {
 
+namespace internal {
+
+// If we want to use functors with both operator() and an Evaluate() method
+// with AutoDiff then this wrapper class here has to be used. Autodiff doesn't
+// support functors that have an Evaluate() function.
+//
+// CostFunctionToFunctor hides the Evaluate() function, because it doesn't
+// derive from CostFunction. Autodiff sees it as a simple functor and will use
+// the operator() as expected.
+template <typename CostFunction>
+struct CostFunctionToFunctor {
+    template <typename... _Args>
+    CostFunctionToFunctor(_Args&&... __args)
+        : cost_function(std::forward<_Args>(__args)...) {}
+
+    template <typename... _Args>
+    bool operator()(_Args&&... __args) const {
+        return cost_function(std::forward<_Args>(__args)...);
+    }
+
+    CostFunction cost_function;
+};
+}
+
 template <int kParameterBlockSize>
 static void BM_ConstantAnalytic(benchmark::State& state) {
   constexpr int num_residuals = 1;
diff --git a/internal/ceres/codegen/CMakeLists.txt b/internal/ceres/codegen/CMakeLists.txt
deleted file mode 100644
index 4bea21f..0000000
--- a/internal/ceres/codegen/CMakeLists.txt
+++ /dev/null
@@ -1,90 +0,0 @@
-# Ceres Solver - A fast non-linear least squares minimizer
-# Copyright 2019 Google Inc. All rights reserved.
-# http://ceres-solver.org/
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are met:
-#
-# * Redistributions of source code must retain the above copyright notice,
-#   this list of conditions and the following disclaimer.
-# * Redistributions in binary form must reproduce the above copyright notice,
-#   this list of conditions and the following disclaimer in the documentation
-#   and/or other materials provided with the distribution.
-# * Neither the name of Google Inc. nor the names of its contributors may be
-#   used to endorse or promote products derived from this software without
-#   specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-# POSSIBILITY OF SUCH DAMAGE.
-#
-# Author: darius.rueckert@fau.de (Darius Rueckert)
-#
-# Testing the AutoDiffCodegen system is more complicated, because function- and
-# constructor calls have side-effects. In C++ the evaluation order and
-# the elision of copies is implementation defined. Between different compilers,
-# some expression might be evaluated in a different order or some copies might be
-# removed.
-#
-# Therefore, we run tests that expect a particular compiler behaviour only on gcc.
-#
-# The semantic tests, which check the correctness by executing the generated code
-# are still run on all platforms.
-if (BUILD_TESTING AND GFLAGS)
-  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    set(CXX_FLAGS_OLD ${CMAKE_CXX_FLAGS})
-    # From the man page:
-    #   The C++ standard allows an implementation to omit creating a
-    #   temporary which is only used to initialize another object of the
-    #   same type.  Specifying -fno-elide-constructors disables that
-    #   optimization, and forces G++ to call the copy constructor in all cases.
-    # We use this flag to get the same results between different versions of
-    # gcc and different optimization levels. Without this flag, testing would
-    # be very painfull and might break when a new compiler version is released.
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-elide-constructors")
-    ceres_test(expression_ref)
-    ceres_test(code_generator)
-    ceres_test(eliminate_nops)
-    set(CMAKE_CXX_FLAGS ${CXX_FLAGS_OLD})
-  endif()
-
-  ceres_test(expression)
-  ceres_test(expression_graph)
-
-  macro (generate_test_functor FUNCTOR_NAME FUNCTOR_FILE)
-    ceres_generate_cost_function_implementation_for_functor(
-      NAME ${FUNCTOR_NAME}
-      INPUT_FILE ${FUNCTOR_FILE}
-      OUTPUT_DIRECTORY tests
-      NAMESPACE test
-      )
-  endmacro()
-
-  # Semantic tests should work on every platform
-  include(CeresCodeGeneration)
-
-
-  generate_test_functor(InputOutputAssignment autodiff_codegen_test.h)
-  generate_test_functor(CompileTimeConstants autodiff_codegen_test.h)
-  generate_test_functor(Assignments autodiff_codegen_test.h)
-  generate_test_functor(BinaryArithmetic autodiff_codegen_test.h)
-  generate_test_functor(UnaryArithmetic autodiff_codegen_test.h)
-  generate_test_functor(BinaryComparison autodiff_codegen_test.h)
-  generate_test_functor(LogicalOperators autodiff_codegen_test.h)
-  generate_test_functor(ScalarFunctions autodiff_codegen_test.h)
-  generate_test_functor(LogicalFunctions autodiff_codegen_test.h)
-  generate_test_functor(Branches autodiff_codegen_test.h)
-  ceres_test(autodiff_codegen)
-  target_link_libraries(autodiff_codegen_test PUBLIC
-    InputOutputAssignment CompileTimeConstants Assignments BinaryArithmetic
-    UnaryArithmetic BinaryComparison LogicalOperators ScalarFunctions
-    LogicalFunctions Branches)
-endif()
diff --git a/internal/ceres/codegen/autodiff_codegen_test.cc b/internal/ceres/codegen/autodiff_codegen_test.cc
deleted file mode 100644
index c6c5cbc..0000000
--- a/internal/ceres/codegen/autodiff_codegen_test.cc
+++ /dev/null
@@ -1,117 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2019 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-// This file tests the Expression class. For each member function one test is
-// included here.
-//
-#include "autodiff_codegen_test.h"
-
-#include "ceres/autodiff_cost_function.h"
-#include "codegen/test_utils.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-class AutoDiffCodegenTest : public testing::TestWithParam<double> {
- public:
-  template <typename CostFunctionType, int kNumResiduals, int... Ns>
-  void TestCostFunction() {
-    using CostFunctorType = CostFunctionToFunctor<CostFunctionType>;
-    CostFunctionType generated_cost_function;
-    CostFunctorType cost_functor;
-    auto* cost_function_ad =
-        new AutoDiffCostFunction<CostFunctorType, kNumResiduals, Ns...>(
-            &cost_functor);
-    auto value = GetParam();
-    CompareCostFunctions(&generated_cost_function,
-                         cost_function_ad,
-                         value,
-                         kRelativeErrorThreshold);
-  }
-  static constexpr double kRelativeErrorThreshold = 0;
-};
-
-TEST_P(AutoDiffCodegenTest, InputOutputAssignment) {
-  TestCostFunction<test::InputOutputAssignment, 7, 4, 2, 1>();
-}
-
-TEST_P(AutoDiffCodegenTest, CompileTimeConstants) {
-  TestCostFunction<test::CompileTimeConstants, 7, 1>();
-}
-
-TEST_P(AutoDiffCodegenTest, Assignments) {
-  TestCostFunction<test::Assignments, 8, 2>();
-}
-
-TEST_P(AutoDiffCodegenTest, BinaryArithmetic) {
-  TestCostFunction<test::BinaryArithmetic, 9, 2>();
-}
-
-TEST_P(AutoDiffCodegenTest, UnaryArithmetic) {
-  TestCostFunction<test::UnaryArithmetic, 3, 1>();
-}
-
-TEST_P(AutoDiffCodegenTest, BinaryComparison) {
-  TestCostFunction<test::BinaryComparison, 12, 2>();
-}
-
-TEST_P(AutoDiffCodegenTest, LogicalOperators) {
-  TestCostFunction<test::LogicalOperators, 8, 3>();
-}
-
-TEST_P(AutoDiffCodegenTest, ScalarFunctions) {
-  TestCostFunction<test::ScalarFunctions, 20, 22>();
-}
-
-TEST_P(AutoDiffCodegenTest, LogicalFunctions) {
-  TestCostFunction<test::LogicalFunctions, 4, 4>();
-}
-
-TEST_P(AutoDiffCodegenTest, Branches) {
-  TestCostFunction<test::Branches, 4, 3>();
-}
-
-INSTANTIATE_TEST_SUITE_P(
-    AutoDiffCodegenTest,
-    AutoDiffCodegenTest,
-    testing::Values(0,
-                    -1,
-                    1,
-                    0.5,
-                    -0.5,
-                    10,
-                    -10,
-                    1e20,
-                    1e-20,
-                    std::numeric_limits<double>::infinity(),
-                    std::numeric_limits<double>::quiet_NaN()));
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/autodiff_codegen_test.h b/internal/ceres/codegen/autodiff_codegen_test.h
deleted file mode 100644
index f5a9f44..0000000
--- a/internal/ceres/codegen/autodiff_codegen_test.h
+++ /dev/null
@@ -1,358 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2020 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-// This file includes unit test functors for every supported expression type.
-// This is similar to expression_ref_test and codegeneration_test, but for the
-// complete pipeline including automatic differentation. For each of the structs
-// below, the Evaluate function is generated using GenerateCodeForFunctor. After
-// that this function is executed with random parameters. The result of the
-// residuals and jacobians is then compared to AutoDiff (without code
-// generation). Of course, the correctness of this module depends on the
-// correctness of autodiff.
-//
-#include <cmath>
-#include <limits>
-
-#include "ceres/codegen/codegen_cost_function.h"
-namespace test {
-
-struct InputOutputAssignment : public ceres::CodegenCostFunction<7, 4, 2, 1> {
-  template <typename T>
-  bool operator()(const T* x0, const T* x1, const T* x2, T* y) const {
-    y[0] = x0[0];
-    y[1] = x0[1];
-    y[2] = x0[2];
-    y[3] = x0[3];
-
-    y[4] = x1[0];
-    y[5] = x1[1];
-
-    y[6] = x2[0];
-    return true;
-  }
-#include "tests/inputoutputassignment.h"
-};
-
-struct CompileTimeConstants : public ceres::CodegenCostFunction<7, 1> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    y[0] = T(0);
-    y[1] = T(1);
-    y[2] = T(-1);
-    y[3] = T(1e-10);
-    y[4] = T(1e10);
-    y[5] = T(std::numeric_limits<double>::infinity());
-    y[6] = T(std::numeric_limits<double>::quiet_NaN());
-
-    return true;
-  }
-#include "tests/compiletimeconstants.h"
-};
-
-struct Assignments : public ceres::CodegenCostFunction<8, 2> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    T b = x0[1];
-    y[0] = a;
-    y[1] = b;
-    y[2] = y[3] = a;
-
-    T c = a;
-    y[4] = c;
-
-    T d(b);
-    y[5] = d;
-
-    y[6] = std::move(c);
-
-    y[7] = std::move(T(T(std::move(T(a)))));
-    return true;
-  }
-#include "tests/assignments.h"
-};
-
-struct BinaryArithmetic : public ceres::CodegenCostFunction<9, 2> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    T b = x0[1];
-    y[0] = a + b;
-    y[1] = a - b;
-    y[2] = a * b;
-    y[3] = a / b;
-
-    y[4] = a;
-    y[4] += b;
-    y[5] = a;
-    y[5] -= b;
-    y[6] = a;
-    y[6] *= b;
-    y[7] = a;
-    y[7] /= b;
-
-    y[8] = a + b * a / a - b + b / a;
-    return true;
-  }
-#include "tests/binaryarithmetic.h"
-};
-
-struct UnaryArithmetic : public ceres::CodegenCostFunction<3, 1> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    y[0] = -a;
-    y[1] = +a;
-    y[2] = a;
-    return true;
-  }
-#include "tests/unaryarithmetic.h"
-};
-
-struct BinaryComparison : public ceres::CodegenCostFunction<12, 2> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    T b = x0[1];
-
-    // For each operator we swap the inputs so both branches are evaluated once.
-    CERES_IF(a < b) { y[0] = T(0); }
-    CERES_ELSE { y[0] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b < a) { y[1] = T(0); }
-    CERES_ELSE { y[1] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(a > b) { y[2] = T(0); }
-    CERES_ELSE { y[2] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b > a) { y[3] = T(0); }
-    CERES_ELSE { y[3] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(a <= b) { y[4] = T(0); }
-    CERES_ELSE { y[4] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b <= a) { y[5] = T(0); }
-    CERES_ELSE { y[5] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(a >= b) { y[6] = T(0); }
-    CERES_ELSE { y[6] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b >= a) { y[7] = T(0); }
-    CERES_ELSE { y[7] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(a == b) { y[8] = T(0); }
-    CERES_ELSE { y[8] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b == a) { y[9] = T(0); }
-    CERES_ELSE { y[9] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(a != b) { y[10] = T(0); }
-    CERES_ELSE { y[10] = T(1); }
-    CERES_ENDIF
-    CERES_IF(b != a) { y[11] = T(0); }
-    CERES_ELSE { y[11] = T(1); }
-    CERES_ENDIF
-
-    return true;
-  }
-#include "tests/binarycomparison.h"
-};
-
-struct LogicalOperators : public ceres::CodegenCostFunction<8, 3> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    T b = x0[1];
-    T c = x0[2];
-    auto r1 = a < b;
-    auto r2 = a < c;
-
-    CERES_IF(r1) { y[0] = T(0); }
-    CERES_ELSE { y[0] = T(1); }
-    CERES_ENDIF
-    CERES_IF(r2) { y[1] = T(0); }
-    CERES_ELSE { y[1] = T(1); }
-    CERES_ENDIF
-    CERES_IF(!r1) { y[2] = T(0); }
-    CERES_ELSE { y[2] = T(1); }
-    CERES_ENDIF
-    CERES_IF(!r2) { y[3] = T(0); }
-    CERES_ELSE { y[3] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(r1 && r2) { y[4] = T(0); }
-    CERES_ELSE { y[4] = T(1); }
-    CERES_ENDIF
-    CERES_IF(!r1 && !r2) { y[5] = T(0); }
-    CERES_ELSE { y[5] = T(1); }
-    CERES_ENDIF
-
-    CERES_IF(r1 || r2) { y[6] = T(0); }
-    CERES_ELSE { y[6] = T(1); }
-    CERES_ENDIF
-    CERES_IF(!r1 || !r2) { y[7] = T(0); }
-    CERES_ELSE { y[7] = T(1); }
-    CERES_ENDIF
-
-    return true;
-  }
-#include "tests/logicaloperators.h"
-};
-
-struct ScalarFunctions : public ceres::CodegenCostFunction<20, 22> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    y[0] = abs(x0[0]);
-    y[1] = acos(x0[1]);
-    y[2] = asin(x0[2]);
-    y[3] = atan(x0[3]);
-    y[4] = cbrt(x0[4]);
-    y[5] = ceil(x0[5]);
-    y[6] = cos(x0[6]);
-    y[7] = cosh(x0[7]);
-    y[8] = exp(x0[8]);
-    y[9] = exp2(x0[9]);
-    y[10] = floor(x0[10]);
-    y[11] = log(x0[11]);
-    y[12] = log2(x0[12]);
-    y[13] = sin(x0[13]);
-    y[14] = sinh(x0[14]);
-    y[15] = sqrt(x0[15]);
-    y[16] = tan(x0[16]);
-    y[17] = tanh(x0[17]);
-    y[18] = atan2(x0[18], x0[19]);
-    y[19] = pow(x0[20], x0[21]);
-    return true;
-  }
-#include "tests/scalarfunctions.h"
-};
-
-struct LogicalFunctions : public ceres::CodegenCostFunction<4, 4> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    using std::isfinite;
-    using std::isinf;
-    using std::isnan;
-    using std::isnormal;
-    T a = x0[0];
-    auto r1 = isfinite(a);
-    auto r2 = isinf(a);
-    auto r3 = isnan(a);
-    auto r4 = isnormal(a);
-
-    CERES_IF(r1) { y[0] = T(0); }
-    CERES_ELSE { y[0] = T(1); }
-    CERES_ENDIF
-    CERES_IF(r2) { y[1] = T(0); }
-    CERES_ELSE { y[1] = T(1); }
-    CERES_ENDIF
-    CERES_IF(r3) { y[2] = T(0); }
-    CERES_ELSE { y[2] = T(1); }
-    CERES_ENDIF
-    CERES_IF(r4) { y[3] = T(0); }
-    CERES_ELSE { y[3] = T(1); }
-    CERES_ENDIF
-
-    return true;
-  }
-#include "tests/logicalfunctions.h"
-};
-
-struct Branches : public ceres::CodegenCostFunction<4, 3> {
-  template <typename T>
-  bool operator()(const T* x0, T* y) const {
-    T a = x0[0];
-    T b = x0[1];
-    T c = x0[2];
-    auto r1 = a < b;
-    auto r2 = a < c;
-    auto r3 = b < c;
-
-    // If without else
-    y[0] = T(0);
-    CERES_IF(r1) { y[0] += T(1); }
-    CERES_ENDIF
-
-    // If else
-    y[1] = T(0);
-    CERES_IF(r1) { y[1] += T(-1); }
-    CERES_ELSE { y[1] += T(1); }
-    CERES_ENDIF
-
-    // Nested if
-    y[2] = T(0);
-    CERES_IF(r1) {
-      y[2] += T(1);
-      CERES_IF(r2) {
-        y[2] += T(4);
-        CERES_IF(r2) { y[2] += T(8); }
-        CERES_ENDIF
-      }
-      CERES_ENDIF
-    }
-    CERES_ENDIF
-
-    // Nested if-else
-    y[3] = T(0);
-    CERES_IF(r1) {
-      y[3] += T(1);
-      CERES_IF(r2) {
-        y[3] += T(2);
-        CERES_IF(r3) { y[3] += T(4); }
-        CERES_ELSE { y[3] += T(8); }
-        CERES_ENDIF
-      }
-      CERES_ELSE {
-        y[3] += T(16);
-        CERES_IF(r3) { y[3] += T(32); }
-        CERES_ELSE { y[3] += T(64); }
-        CERES_ENDIF
-      }
-      CERES_ENDIF
-    }
-    CERES_ELSE {
-      y[3] += T(128);
-      CERES_IF(r2) { y[3] += T(256); }
-      CERES_ELSE { y[3] += T(512); }
-      CERES_ENDIF
-    }
-    CERES_ENDIF
-
-    return true;
-  }
-#include "tests/branches.h"
-};
-
-}  // namespace test
diff --git a/internal/ceres/codegen/code_generator_test.cc b/internal/ceres/codegen/code_generator_test.cc
deleted file mode 100644
index f799a75..0000000
--- a/internal/ceres/codegen/code_generator_test.cc
+++ /dev/null
@@ -1,535 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2019 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-#define CERES_CODEGEN
-
-#include "ceres/codegen/internal/code_generator.h"
-
-#include "ceres/codegen/internal/expression_graph.h"
-#include "ceres/codegen/internal/expression_ref.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-static void GenerateAndCheck(const ExpressionGraph& graph,
-                             const std::vector<std::string>& reference) {
-  CodeGenerator::Options generator_options;
-  CodeGenerator gen(graph, generator_options);
-  auto code = gen.Generate();
-  EXPECT_EQ(code.size(), reference.size());
-
-  for (int i = 0; i < std::min(code.size(), reference.size()); ++i) {
-    EXPECT_EQ(code[i], reference[i]) << "Invalid Line: " << (i + 1);
-  }
-}
-
-using T = ExpressionRef;
-
-TEST(CodeGenerator, Empty) {
-  StartRecordingExpressions();
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{", "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-// Now we add one TEST for each ExpressionType.
-TEST(CodeGenerator, COMPILE_TIME_CONSTANT) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(123.5);
-  T c = T(1 + 1);
-  T d = T(std::numeric_limits<double>::infinity());
-  T e = T(-std::numeric_limits<double>::infinity());
-  T f = T(std::numeric_limits<double>::quiet_NaN());
-  T g;  // Uninitialized variables are 0 initialized.
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {
-      "{",
-      "  double v_0;",
-      "  double v_1;",
-      "  double v_2;",
-      "  double v_3;",
-      "  double v_4;",
-      "  double v_5;",
-      "  double v_6;",
-      "  v_0 = 0;",
-      "  v_1 = 123.5;",
-      "  v_2 = 2;",
-      "  v_3 = std::numeric_limits<double>::infinity();",
-      "  v_4 = -std::numeric_limits<double>::infinity();",
-      "  v_5 = std::numeric_limits<double>::quiet_NaN();",
-      "  v_6 = 0;",
-      "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, INPUT_ASSIGNMENT) {
-  double local_variable = 5.0;
-  StartRecordingExpressions();
-  T a = CERES_LOCAL_VARIABLE(T, local_variable);
-  T b = MakeParameter("parameters[0][0]");
-  T c = a + b;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  v_0 = local_variable;",
-                                            "  v_1 = parameters[0][0];",
-                                            "  v_2 = v_0 + v_1;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, OUTPUT_ASSIGNMENT) {
-  StartRecordingExpressions();
-  T a = 1;
-  T b = 0;
-  MakeOutput(a, "residual[0]");
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  v_0 = 1;",
-                                            "  v_1 = 0;",
-                                            "  residual[0] = v_0;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, ASSIGNMENT) {
-  StartRecordingExpressions();
-  T a = T(0);  // 0
-  T b = T(1);  // 1
-  T c = a;     // 2
-  a = b;       // 3
-  a = a + b;   // 4 + 5
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  double v_4;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = v_0;",
-                                            "  v_0 = v_1;",
-                                            "  v_4 = v_0 + v_1;",
-                                            "  v_0 = v_4;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, BINARY_ARITHMETIC_SIMPLE) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  T r1 = a + b;
-  T r2 = a - b;
-  T r3 = a * b;
-  T r4 = a / b;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  double v_3;",
-                                            "  double v_4;",
-                                            "  double v_5;",
-                                            "  v_0 = 1;",
-                                            "  v_1 = 2;",
-                                            "  v_2 = v_0 + v_1;",
-                                            "  v_3 = v_0 - v_1;",
-                                            "  v_4 = v_0 * v_1;",
-                                            "  v_5 = v_0 / v_1;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, BINARY_ARITHMETIC_NESTED) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  T r1 = b - a * (a + b) / a;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  double v_3;",
-                                            "  double v_4;",
-                                            "  double v_5;",
-                                            "  v_0 = 1;",
-                                            "  v_1 = 2;",
-                                            "  v_2 = v_0 + v_1;",
-                                            "  v_3 = v_0 * v_2;",
-                                            "  v_4 = v_3 / v_0;",
-                                            "  v_5 = v_1 - v_4;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, BINARY_ARITHMETIC_COMPOUND) {
-  // For each binary compound arithmetic operation, two lines are generated:
-  //    - The actual operation assigning to a new temporary variable
-  //    - An assignment from the temporary to the lhs
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  a += b;
-  a -= b;
-  a *= b;
-  a /= b;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  double v_4;",
-                                            "  double v_6;",
-                                            "  double v_8;",
-                                            "  v_0 = 1;",
-                                            "  v_1 = 2;",
-                                            "  v_2 = v_0 + v_1;",
-                                            "  v_0 = v_2;",
-                                            "  v_4 = v_0 - v_1;",
-                                            "  v_0 = v_4;",
-                                            "  v_6 = v_0 * v_1;",
-                                            "  v_0 = v_6;",
-                                            "  v_8 = v_0 / v_1;",
-                                            "  v_0 = v_8;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, UNARY_ARITHMETIC) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T r1 = -a;
-  T r2 = +a;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = -v_0;",
-                                            "  v_2 = +v_0;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, BINARY_COMPARISON) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-  auto r1 = a < b;
-  auto r2 = a <= b;
-  auto r3 = a > b;
-  auto r4 = a >= b;
-  auto r5 = a == b;
-  auto r6 = a != b;
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  bool v_2;",
-                                            "  bool v_3;",
-                                            "  bool v_4;",
-                                            "  bool v_5;",
-                                            "  bool v_6;",
-                                            "  bool v_7;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = v_0 < v_1;",
-                                            "  v_3 = v_0 <= v_1;",
-                                            "  v_4 = v_0 > v_1;",
-                                            "  v_5 = v_0 >= v_1;",
-                                            "  v_6 = v_0 == v_1;",
-                                            "  v_7 = v_0 != v_1;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, LOGICAL_OPERATORS) {
-  // Tests binary logical operators &&, || and the unary logical operator !
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-  auto r1 = a < b;
-  auto r2 = a <= b;
-
-  auto r3 = r1 && r2;
-  auto r4 = r1 || r2;
-  auto r5 = !r1;
-
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  bool v_2;",
-                                            "  bool v_3;",
-                                            "  bool v_4;",
-                                            "  bool v_5;",
-                                            "  bool v_6;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = v_0 < v_1;",
-                                            "  v_3 = v_0 <= v_1;",
-                                            "  v_4 = v_2 && v_3;",
-                                            "  v_5 = v_2 || v_3;",
-                                            "  v_6 = !v_2;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, FUNCTION_CALL) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-
-  abs(a);
-  acos(a);
-  asin(a);
-  atan(a);
-  cbrt(a);
-  ceil(a);
-  cos(a);
-  cosh(a);
-  exp(a);
-  exp2(a);
-  floor(a);
-  log(a);
-  log2(a);
-  sin(a);
-  sinh(a);
-  sqrt(a);
-  tan(a);
-  tanh(a);
-  atan2(a, b);
-  pow(a, b);
-
-  auto graph = StopRecordingExpressions();
-
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  double v_3;",
-                                            "  double v_4;",
-                                            "  double v_5;",
-                                            "  double v_6;",
-                                            "  double v_7;",
-                                            "  double v_8;",
-                                            "  double v_9;",
-                                            "  double v_10;",
-                                            "  double v_11;",
-                                            "  double v_12;",
-                                            "  double v_13;",
-                                            "  double v_14;",
-                                            "  double v_15;",
-                                            "  double v_16;",
-                                            "  double v_17;",
-                                            "  double v_18;",
-                                            "  double v_19;",
-                                            "  double v_20;",
-                                            "  double v_21;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = std::abs(v_0);",
-                                            "  v_3 = std::acos(v_0);",
-                                            "  v_4 = std::asin(v_0);",
-                                            "  v_5 = std::atan(v_0);",
-                                            "  v_6 = std::cbrt(v_0);",
-                                            "  v_7 = std::ceil(v_0);",
-                                            "  v_8 = std::cos(v_0);",
-                                            "  v_9 = std::cosh(v_0);",
-                                            "  v_10 = std::exp(v_0);",
-                                            "  v_11 = std::exp2(v_0);",
-                                            "  v_12 = std::floor(v_0);",
-                                            "  v_13 = std::log(v_0);",
-                                            "  v_14 = std::log2(v_0);",
-                                            "  v_15 = std::sin(v_0);",
-                                            "  v_16 = std::sinh(v_0);",
-                                            "  v_17 = std::sqrt(v_0);",
-                                            "  v_18 = std::tan(v_0);",
-                                            "  v_19 = std::tanh(v_0);",
-                                            "  v_20 = std::atan2(v_0, v_1);",
-                                            "  v_21 = std::pow(v_0, v_1);",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, LOGICAL_FUNCTION_CALL) {
-  StartRecordingExpressions();
-  T a = T(1);
-
-  isfinite(a);
-  isinf(a);
-  isnan(a);
-  isnormal(a);
-
-  auto graph = StopRecordingExpressions();
-
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  bool v_1;",
-                                            "  bool v_2;",
-                                            "  bool v_3;",
-                                            "  bool v_4;",
-                                            "  v_0 = 1;",
-                                            "  v_1 = std::isfinite(v_0);",
-                                            "  v_2 = std::isinf(v_0);",
-                                            "  v_3 = std::isnan(v_0);",
-                                            "  v_4 = std::isnormal(v_0);",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, IF_SIMPLE) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-  auto r1 = a < b;
-  CERES_IF(r1) {}
-  CERES_ELSE {}
-  CERES_ENDIF;
-
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  bool v_2;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = v_0 < v_1;",
-                                            "  if (v_2) {",
-                                            "  } else {",
-                                            "  }",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, IF_ASSIGNMENT) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-  auto r1 = a < b;
-
-  T result = 0;
-  CERES_IF(r1) { result = 5.0; }
-  CERES_ELSE { result = 6.0; }
-  CERES_ENDIF;
-  MakeOutput(result, "result");
-
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  bool v_2;",
-                                            "  double v_3;",
-                                            "  double v_5;",
-                                            "  double v_8;",
-                                            "  double v_11;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = v_0 < v_1;",
-                                            "  v_3 = 0;",
-                                            "  if (v_2) {",
-                                            "    v_5 = 5;",
-                                            "    v_3 = v_5;",
-                                            "  } else {",
-                                            "    v_8 = 6;",
-                                            "    v_3 = v_8;",
-                                            "  }",
-                                            "  result = v_3;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, IF_NESTED_ASSIGNMENT) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(1);
-
-  T result = 0;
-  CERES_IF(a <= b) {
-    result = 5.0;
-    CERES_IF(a == b) { result = 7.0; }
-    CERES_ENDIF;
-  }
-  CERES_ELSE { result = 6.0; }
-  CERES_ENDIF;
-  MakeOutput(result, "result");
-
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{",
-                                            "  double v_0;",
-                                            "  double v_1;",
-                                            "  double v_2;",
-                                            "  bool v_3;",
-                                            "  double v_5;",
-                                            "  bool v_7;",
-                                            "  double v_9;",
-                                            "  double v_13;",
-                                            "  double v_16;",
-                                            "  v_0 = 0;",
-                                            "  v_1 = 1;",
-                                            "  v_2 = 0;",
-                                            "  v_3 = v_0 <= v_1;",
-                                            "  if (v_3) {",
-                                            "    v_5 = 5;",
-                                            "    v_2 = v_5;",
-                                            "    v_7 = v_0 == v_1;",
-                                            "    if (v_7) {",
-                                            "      v_9 = 7;",
-                                            "      v_2 = v_9;",
-                                            "    }",
-                                            "  } else {",
-                                            "    v_13 = 6;",
-                                            "    v_2 = v_13;",
-                                            "  }",
-                                            "  result = v_2;",
-                                            "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-TEST(CodeGenerator, COMMENT) {
-  StartRecordingExpressions();
-  CERES_COMMENT("Hello");
-  auto graph = StopRecordingExpressions();
-  std::vector<std::string> expected_code = {"{", "  // Hello", "}"};
-  GenerateAndCheck(graph, expected_code);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/eliminate_nops_test.cc b/internal/ceres/codegen/eliminate_nops_test.cc
deleted file mode 100644
index 4b196b1..0000000
--- a/internal/ceres/codegen/eliminate_nops_test.cc
+++ /dev/null
@@ -1,110 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2020 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-#define CERES_CODEGEN
-
-#include "ceres/codegen/internal/eliminate_nops.h"
-
-#include "ceres/codegen/internal/code_generator.h"
-#include "ceres/codegen/internal/expression_graph.h"
-#include "ceres/codegen/internal/expression_ref.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-using T = ExpressionRef;
-
-TEST(EliminateNops, SimpleLinear) {
-  StartRecordingExpressions();
-  {
-    T a = T(0);
-    // The Expression default constructor creates a NOP.
-    AddExpressionToGraph(Expression());
-    AddExpressionToGraph(Expression());
-    T b = T(2);
-    AddExpressionToGraph(Expression());
-    MakeOutput(b, "residual[0]");
-    AddExpressionToGraph(Expression());
-  }
-  auto graph = StopRecordingExpressions();
-
-  StartRecordingExpressions();
-  {
-    T a = T(0);
-    T b = T(2);
-    MakeOutput(b, "residual[0]");
-  }
-  auto reference = StopRecordingExpressions();
-
-  auto summary = EliminateNops(&graph);
-  EXPECT_TRUE(summary.expression_graph_changed);
-  EXPECT_EQ(graph, reference);
-}
-
-TEST(EliminateNops, Branches) {
-  StartRecordingExpressions();
-  {
-    T a = T(0);
-    // The Expression default constructor creates a NOP.
-    AddExpressionToGraph(Expression());
-    AddExpressionToGraph(Expression());
-    T b = T(2);
-    CERES_IF(a < b) {
-      AddExpressionToGraph(Expression());
-      T c = T(3);
-    }
-    CERES_ELSE {
-      AddExpressionToGraph(Expression());
-      MakeOutput(b, "residual[0]");
-      AddExpressionToGraph(Expression());
-    }
-    CERES_ENDIF
-    AddExpressionToGraph(Expression());
-  }
-  auto graph = StopRecordingExpressions();
-
-  StartRecordingExpressions();
-  {
-    T a = T(0);
-    T b = T(2);
-    CERES_IF(a < b) { T c = T(3); }
-    CERES_ELSE { MakeOutput(b, "residual[0]"); }
-    CERES_ENDIF
-  }
-  auto reference = StopRecordingExpressions();
-
-  auto summary = EliminateNops(&graph);
-  EXPECT_TRUE(summary.expression_graph_changed);
-  EXPECT_EQ(graph, reference);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/expression_graph_test.cc b/internal/ceres/codegen/expression_graph_test.cc
deleted file mode 100644
index 4f4f0ec..0000000
--- a/internal/ceres/codegen/expression_graph_test.cc
+++ /dev/null
@@ -1,286 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2019 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-// This file tests the ExpressionGraph class. This test depends on the
-// correctness of Expression.
-//
-#include "ceres/codegen/internal/expression_graph.h"
-
-#include "ceres/codegen/internal/expression.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-TEST(ExpressionGraph, Size) {
-  ExpressionGraph graph;
-  EXPECT_EQ(graph.Size(), 0);
-  // Insert 3 NOPs
-  graph.InsertBack(Expression());
-  graph.InsertBack(Expression());
-  graph.InsertBack(Expression());
-  EXPECT_EQ(graph.Size(), 3);
-}
-
-TEST(ExpressionGraph, Recording) {
-  EXPECT_EQ(GetCurrentExpressionGraph(), nullptr);
-  StartRecordingExpressions();
-  EXPECT_NE(GetCurrentExpressionGraph(), nullptr);
-  auto graph = StopRecordingExpressions();
-  EXPECT_EQ(graph, ExpressionGraph());
-  EXPECT_EQ(GetCurrentExpressionGraph(), nullptr);
-}
-
-TEST(ExpressionGraph, InsertBackControl) {
-  // Control expression are inserted to the back without any modifications.
-  auto expr1 = Expression::CreateIf(ExpressionId(0));
-  auto expr2 = Expression::CreateElse();
-  auto expr3 = Expression::CreateEndIf();
-
-  ExpressionGraph graph;
-  graph.InsertBack(expr1);
-  graph.InsertBack(expr2);
-  graph.InsertBack(expr3);
-
-  EXPECT_EQ(graph.Size(), 3);
-  EXPECT_EQ(graph.ExpressionForId(0), expr1);
-  EXPECT_EQ(graph.ExpressionForId(1), expr2);
-  EXPECT_EQ(graph.ExpressionForId(2), expr3);
-}
-
-TEST(ExpressionGraph, InsertBackNewVariable) {
-  // If an arithmetic expression with lhs=kinvalidValue is inserted in the back,
-  // then a new variable name is created and set to the lhs_id.
-  auto expr1 = Expression::CreateCompileTimeConstant(42);
-  auto expr2 = Expression::CreateCompileTimeConstant(10);
-  auto expr3 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(0), ExpressionId(1));
-
-  ExpressionGraph graph;
-  graph.InsertBack(expr1);
-  graph.InsertBack(expr2);
-  graph.InsertBack(expr3);
-  EXPECT_EQ(graph.Size(), 3);
-
-  // The ExpressionGraph has a copy of the inserted expression with the correct
-  // lhs_ids. We set them here manually for comparision.
-  expr1.set_lhs_id(0);
-  expr2.set_lhs_id(1);
-  expr3.set_lhs_id(2);
-  EXPECT_EQ(graph.ExpressionForId(0), expr1);
-  EXPECT_EQ(graph.ExpressionForId(1), expr2);
-  EXPECT_EQ(graph.ExpressionForId(2), expr3);
-}
-
-TEST(ExpressionGraph, InsertBackExistingVariable) {
-  auto expr1 = Expression::CreateCompileTimeConstant(42);
-  auto expr2 = Expression::CreateCompileTimeConstant(10);
-  auto expr3 = Expression::CreateAssignment(1, 0);
-
-  ExpressionGraph graph;
-  graph.InsertBack(expr1);
-  graph.InsertBack(expr2);
-  graph.InsertBack(expr3);
-  EXPECT_EQ(graph.Size(), 3);
-
-  expr1.set_lhs_id(0);
-  expr2.set_lhs_id(1);
-  expr3.set_lhs_id(1);
-  EXPECT_EQ(graph.ExpressionForId(0), expr1);
-  EXPECT_EQ(graph.ExpressionForId(1), expr2);
-  EXPECT_EQ(graph.ExpressionForId(2), expr3);
-}
-
-TEST(ExpressionGraph, DependsOn) {
-  ExpressionGraph graph;
-  graph.InsertBack(Expression::CreateCompileTimeConstant(42));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(10));
-  graph.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(0), ExpressionId(1)));
-  graph.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(2), ExpressionId(0)));
-
-  // Code:
-  // v_0 = 42
-  // v_1 = 10
-  // v_2 = v_0 + v_1
-  // v_3 = v_2 + v_0
-
-  // Direct dependencies dependency check
-  ASSERT_TRUE(graph.DependsOn(2, 0));
-  ASSERT_TRUE(graph.DependsOn(2, 1));
-  ASSERT_TRUE(graph.DependsOn(3, 2));
-  ASSERT_TRUE(graph.DependsOn(3, 0));
-  ASSERT_FALSE(graph.DependsOn(1, 0));
-  ASSERT_FALSE(graph.DependsOn(1, 1));
-  ASSERT_FALSE(graph.DependsOn(2, 3));
-
-  // Recursive test
-  ASSERT_TRUE(graph.DependsOn(3, 1));
-}
-
-TEST(ExpressionGraph, FindMatchingEndif) {
-  ExpressionGraph graph;
-  graph.InsertBack(Expression::CreateCompileTimeConstant(1));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(2));
-  graph.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateElse());
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateElse());
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateIf(2));  // < if without matching endif
-  EXPECT_EQ(graph.Size(), 12);
-
-  // Code              <id>
-  // v_0 = 1            0
-  // v_1 = 2            1
-  // v_2 = v_0 < v_1    2
-  // IF (v_2)           3
-  //   IF (v_2)         4
-  //   ELSE             5
-  //   ENDIF            6
-  // ELSE               7
-  //   IF (v_2)         8
-  //   ENDIF            9
-  // ENDIF              10
-  // IF(v_2)            11
-
-  EXPECT_EQ(graph.FindMatchingEndif(3), 10);
-  EXPECT_EQ(graph.FindMatchingEndif(4), 6);
-  EXPECT_EQ(graph.FindMatchingEndif(8), 9);
-  EXPECT_EQ(graph.FindMatchingEndif(11), kInvalidExpressionId);
-}
-
-TEST(ExpressionGraph, FindMatchingElse) {
-  ExpressionGraph graph;
-  graph.InsertBack(Expression::CreateCompileTimeConstant(1));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(2));
-  graph.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateElse());
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateElse());
-  graph.InsertBack(Expression::CreateIf(2));
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateEndIf());
-  graph.InsertBack(Expression::CreateIf(2));  // < if without matching endif
-  EXPECT_EQ(graph.Size(), 12);
-
-  // Code              <id>
-  // v_0 = 1            0
-  // v_1 = 2            1
-  // v_2 = v_0 < v_1    2
-  // IF (v_2)           3
-  //   IF (v_2)         4
-  //   ELSE             5
-  //   ENDIF            6
-  // ELSE               7
-  //   IF (v_2)         8
-  //   ENDIF            9
-  // ENDIF              10
-  // IF(v_2)            11
-
-  EXPECT_EQ(graph.FindMatchingElse(3), 7);
-  EXPECT_EQ(graph.FindMatchingElse(4), 5);
-  EXPECT_EQ(graph.FindMatchingElse(8), kInvalidExpressionId);
-  EXPECT_EQ(graph.FindMatchingEndif(11), kInvalidExpressionId);
-}
-
-TEST(ExpressionGraph, InsertExpression_UpdateReferences) {
-  // This test checks if references to shifted expressions are updated
-  // accordingly.
-  ExpressionGraph graph;
-  graph.InsertBack(Expression::CreateCompileTimeConstant(42));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(10));
-  graph.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(0), ExpressionId(1)));
-  // Code:
-  // v_0 = 42
-  // v_1 = 10
-  // v_2 = v_0 + v_1
-
-  // Insert another compile time constant at the beginning
-  graph.Insert(0, Expression::CreateCompileTimeConstant(5));
-  // This should shift all indices like this:
-  // v_0 = 5
-  // v_1 = 42
-  // v_2 = 10
-  // v_3 = v_1 + v_2
-
-  // Test by inserting it in the correct order
-  ExpressionGraph ref;
-  ref.InsertBack(Expression::CreateCompileTimeConstant(5));
-  ref.InsertBack(Expression::CreateCompileTimeConstant(42));
-  ref.InsertBack(Expression::CreateCompileTimeConstant(10));
-  ref.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(1), ExpressionId(2)));
-  EXPECT_EQ(graph.Size(), ref.Size());
-  EXPECT_EQ(graph, ref);
-}
-
-TEST(ExpressionGraph, Erase) {
-  // This test checks if references to shifted expressions are updated
-  // accordingly.
-  ExpressionGraph graph;
-  graph.InsertBack(Expression::CreateCompileTimeConstant(42));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(10));
-  graph.InsertBack(Expression::CreateCompileTimeConstant(3));
-  graph.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(0), ExpressionId(2)));
-  // Code:
-  // v_0 = 42
-  // v_1 = 10
-  // v_2 = 3
-  // v_3 = v_0 + v_2
-
-  // Erase the unused expression v_1 = 10
-  graph.Erase(1);
-  // This should shift all indices like this:
-  // v_0 = 42
-  // v_1 = 3
-  // v_2 = v_0 + v_1
-
-  // Test by inserting it in the correct order
-  ExpressionGraph ref;
-  ref.InsertBack(Expression::CreateCompileTimeConstant(42));
-  ref.InsertBack(Expression::CreateCompileTimeConstant(3));
-  ref.InsertBack(Expression::CreateBinaryArithmetic(
-      "+", ExpressionId(0), ExpressionId(1)));
-  EXPECT_EQ(graph.Size(), ref.Size());
-  EXPECT_EQ(graph, ref);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/expression_ref_test.cc b/internal/ceres/codegen/expression_ref_test.cc
deleted file mode 100644
index c9a118b..0000000
--- a/internal/ceres/codegen/expression_ref_test.cc
+++ /dev/null
@@ -1,411 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2019 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-// This file tests the ExpressionRef class. This test depends on the
-// correctness of Expression and ExpressionGraph.
-//
-#define CERES_CODEGEN
-
-#include "ceres/codegen/internal/expression_ref.h"
-
-#include "ceres/codegen/internal/expression_graph.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-using T = ExpressionRef;
-
-TEST(ExpressionRef, COMPILE_TIME_CONSTANT) {
-  StartRecordingExpressions();
-  T a = T(0);
-  T b = T(123.5);
-  T c = T(1 + 1);
-  T d;  // Uninitialized variables are also compile time constants
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(0));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(123.5));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(0));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, INPUT_ASSIGNMENT) {
-  double local_variable = 5.0;
-  StartRecordingExpressions();
-  T a = CERES_LOCAL_VARIABLE(T, local_variable);
-  T b = MakeParameter("parameters[0][0]");
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateInputAssignment("local_variable"));
-  reference.InsertBack(Expression::CreateInputAssignment("parameters[0][0]"));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, OUTPUT_ASSIGNMENT) {
-  StartRecordingExpressions();
-  T a = 1;
-  T b = 0;
-  MakeOutput(a, "residual[0]");
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(0));
-  reference.InsertBack(Expression::CreateOutputAssignment(0, "residual[0]"));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, Assignment) {
-  StartRecordingExpressions();
-  T a = 1;
-  T b = 2;
-  b = a;
-  auto graph = StopRecordingExpressions();
-  EXPECT_EQ(graph.Size(), 3);
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateAssignment(1, 0));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, AssignmentCreate) {
-  StartRecordingExpressions();
-  T a = 2;
-  T b = a;
-  auto graph = StopRecordingExpressions();
-  EXPECT_EQ(graph.Size(), 2);
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateAssignment(kInvalidExpressionId, 0));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, MoveAssignment) {
-  StartRecordingExpressions();
-  T a = 1;
-  T b = 2;
-  b = std::move(a);
-  auto graph = StopRecordingExpressions();
-  EXPECT_EQ(graph.Size(), 3);
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateAssignment(1, 0));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, BINARY_ARITHMETIC_SIMPLE) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  T r1 = a + b;
-  T r2 = a - b;
-  T r3 = a * b;
-  T r4 = a / b;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("+", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("-", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("*", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("/", 0, 1));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, BINARY_ARITHMETIC_NESTED) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  T r1 = b - a * (a + b) / a;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("+", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("*", 0, 2));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("/", 3, 0));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("-", 1, 4));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, BINARY_ARITHMETIC_COMPOUND) {
-  // For each binary compound arithmetic operation, two lines are generated:
-  //    - The actual operation assigning to a new temporary variable
-  //    - An assignment from the temporary to the lhs
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  a += b;
-  a -= b;
-  a *= b;
-  a /= b;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("+", 0, 1));
-  reference.InsertBack(Expression::CreateAssignment(0, 2));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("-", 0, 1));
-  reference.InsertBack(Expression::CreateAssignment(0, 4));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("*", 0, 1));
-  reference.InsertBack(Expression::CreateAssignment(0, 6));
-  reference.InsertBack(Expression::CreateBinaryArithmetic("/", 0, 1));
-  reference.InsertBack(Expression::CreateAssignment(0, 8));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, UNARY_ARITHMETIC) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T r1 = -a;
-  T r2 = +a;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateUnaryArithmetic("-", 0));
-  reference.InsertBack(Expression::CreateUnaryArithmetic("+", 0));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, BINARY_COMPARISON) {
-  using BOOL = ComparisonExpressionRef;
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  BOOL r1 = a < b;
-  BOOL r2 = a <= b;
-  BOOL r3 = a > b;
-  BOOL r4 = a >= b;
-  BOOL r5 = a == b;
-  BOOL r6 = a != b;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("<=", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare(">", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare(">=", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("==", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("!=", 0, 1));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, LOGICAL_OPERATORS) {
-  using BOOL = ComparisonExpressionRef;
-  // Tests binary logical operators &&, || and the unary logical operator !
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  BOOL r1 = a < b;
-  BOOL r2 = a <= b;
-  BOOL r3 = r1 && r2;
-  BOOL r4 = r1 || r2;
-  BOOL r5 = !r1;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("<=", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("&&", 2, 3));
-  reference.InsertBack(Expression::CreateBinaryCompare("||", 2, 3));
-  reference.InsertBack(Expression::CreateLogicalNegation(2));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, SCALAR_FUNCTION_CALL) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  abs(a);
-  acos(a);
-  asin(a);
-  atan(a);
-  cbrt(a);
-  ceil(a);
-  cos(a);
-  cosh(a);
-  exp(a);
-  exp2(a);
-  floor(a);
-  log(a);
-  log2(a);
-  sin(a);
-  sinh(a);
-  sqrt(a);
-  tan(a);
-  tanh(a);
-  atan2(a, b);
-  pow(a, b);
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::abs", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::acos", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::asin", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::atan", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::cbrt", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::ceil", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::cos", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::cosh", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::exp", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::exp2", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::floor", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::log", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::log2", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::sin", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::sinh", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::sqrt", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::tan", {0}));
-  reference.InsertBack(Expression::CreateScalarFunctionCall("std::tanh", {0}));
-  reference.InsertBack(
-      Expression::CreateScalarFunctionCall("std::atan2", {0, 1}));
-  reference.InsertBack(
-      Expression::CreateScalarFunctionCall("std::pow", {0, 1}));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, LOGICAL_FUNCTION_CALL) {
-  StartRecordingExpressions();
-  T a = T(1);
-  isfinite(a);
-  isinf(a);
-  isnan(a);
-  isnormal(a);
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(
-      Expression::CreateLogicalFunctionCall("std::isfinite", {0}));
-  reference.InsertBack(
-      Expression::CreateLogicalFunctionCall("std::isinf", {0}));
-  reference.InsertBack(
-      Expression::CreateLogicalFunctionCall("std::isnan", {0}));
-  reference.InsertBack(
-      Expression::CreateLogicalFunctionCall("std::isnormal", {0}));
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, IF) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  auto r1 = a < b;
-  CERES_IF(r1) {}
-  CERES_ENDIF;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  reference.InsertBack(Expression::CreateIf(2));
-  reference.InsertBack(Expression::CreateEndIf());
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, IF_ELSE) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  auto r1 = a < b;
-  CERES_IF(r1) {}
-  CERES_ELSE {}
-  CERES_ENDIF;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  reference.InsertBack(Expression::CreateIf(2));
-  reference.InsertBack(Expression::CreateElse());
-  reference.InsertBack(Expression::CreateEndIf());
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, IF_NESTED) {
-  StartRecordingExpressions();
-  T a = T(1);
-  T b = T(2);
-  auto r1 = a < b;
-  auto r2 = a == b;
-  CERES_IF(r1) {
-    CERES_IF(r2) {}
-    CERES_ENDIF;
-  }
-  CERES_ELSE {}
-  CERES_ENDIF;
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateCompileTimeConstant(1));
-  reference.InsertBack(Expression::CreateCompileTimeConstant(2));
-  reference.InsertBack(Expression::CreateBinaryCompare("<", 0, 1));
-  reference.InsertBack(Expression::CreateBinaryCompare("==", 0, 1));
-  reference.InsertBack(Expression::CreateIf(2));
-  reference.InsertBack(Expression::CreateIf(3));
-  reference.InsertBack(Expression::CreateEndIf());
-  reference.InsertBack(Expression::CreateElse());
-  reference.InsertBack(Expression::CreateEndIf());
-  EXPECT_EQ(reference, graph);
-}
-
-TEST(ExpressionRef, COMMENT) {
-  StartRecordingExpressions();
-  CERES_COMMENT("This is a comment");
-  auto graph = StopRecordingExpressions();
-
-  ExpressionGraph reference;
-  reference.InsertBack(Expression::CreateComment("This is a comment"));
-  EXPECT_EQ(reference, graph);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/expression_test.cc b/internal/ceres/codegen/expression_test.cc
deleted file mode 100644
index 65daf69..0000000
--- a/internal/ceres/codegen/expression_test.cc
+++ /dev/null
@@ -1,325 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2019 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-//
-// This file tests the Expression class. For each member function one test is
-// included here.
-//
-#include "ceres/codegen/internal/expression.h"
-#include "gtest/gtest.h"
-
-namespace ceres {
-namespace internal {
-
-TEST(Expression, ConstructorAndAccessors) {
-  Expression expr(ExpressionType::LOGICAL_NEGATION,
-                  ExpressionReturnType::BOOLEAN,
-                  12345,
-                  {1, 5, 8, 10},
-                  "TestConstructor",
-                  57.25);
-  EXPECT_EQ(expr.type(), ExpressionType::LOGICAL_NEGATION);
-  EXPECT_EQ(expr.return_type(), ExpressionReturnType::BOOLEAN);
-  EXPECT_EQ(expr.lhs_id(), 12345);
-  EXPECT_EQ(expr.arguments(), std::vector<ExpressionId>({1, 5, 8, 10}));
-  EXPECT_EQ(expr.name(), "TestConstructor");
-  EXPECT_EQ(expr.value(), 57.25);
-}
-
-TEST(Expression, CreateFunctions) {
-  // The default constructor creates a NOP!
-  EXPECT_EQ(Expression(),
-            Expression(ExpressionType::NOP,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {},
-                       "",
-                       0));
-
-  EXPECT_EQ(Expression::CreateCompileTimeConstant(72),
-            Expression(ExpressionType::COMPILE_TIME_CONSTANT,
-                       ExpressionReturnType::SCALAR,
-                       kInvalidExpressionId,
-                       {},
-                       "",
-                       72));
-
-  EXPECT_EQ(Expression::CreateInputAssignment("arguments[0][0]"),
-            Expression(ExpressionType::INPUT_ASSIGNMENT,
-                       ExpressionReturnType::SCALAR,
-                       kInvalidExpressionId,
-                       {},
-                       "arguments[0][0]",
-                       0));
-
-  EXPECT_EQ(Expression::CreateOutputAssignment(ExpressionId(5), "residuals[3]"),
-            Expression(ExpressionType::OUTPUT_ASSIGNMENT,
-                       ExpressionReturnType::SCALAR,
-                       kInvalidExpressionId,
-                       {5},
-                       "residuals[3]",
-                       0));
-
-  EXPECT_EQ(Expression::CreateAssignment(ExpressionId(3), ExpressionId(5)),
-            Expression(ExpressionType::ASSIGNMENT,
-                       ExpressionReturnType::SCALAR,
-                       3,
-                       {5},
-                       "",
-                       0));
-
-  EXPECT_EQ(
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5)),
-      Expression(ExpressionType::BINARY_ARITHMETIC,
-                 ExpressionReturnType::SCALAR,
-                 kInvalidExpressionId,
-                 {3, 5},
-                 "+",
-                 0));
-
-  EXPECT_EQ(Expression::CreateUnaryArithmetic("-", ExpressionId(5)),
-            Expression(ExpressionType::UNARY_ARITHMETIC,
-                       ExpressionReturnType::SCALAR,
-                       kInvalidExpressionId,
-                       {5},
-                       "-",
-                       0));
-
-  EXPECT_EQ(
-      Expression::CreateBinaryCompare("<", ExpressionId(3), ExpressionId(5)),
-      Expression(ExpressionType::BINARY_COMPARISON,
-                 ExpressionReturnType::BOOLEAN,
-                 kInvalidExpressionId,
-                 {3, 5},
-                 "<",
-                 0));
-
-  EXPECT_EQ(Expression::CreateLogicalNegation(ExpressionId(5)),
-            Expression(ExpressionType::LOGICAL_NEGATION,
-                       ExpressionReturnType::BOOLEAN,
-                       kInvalidExpressionId,
-                       {5},
-                       "",
-                       0));
-
-  EXPECT_EQ(Expression::CreateScalarFunctionCall(
-                "pow", {ExpressionId(3), ExpressionId(5)}),
-            Expression(ExpressionType::FUNCTION_CALL,
-                       ExpressionReturnType::SCALAR,
-                       kInvalidExpressionId,
-                       {3, 5},
-                       "pow",
-                       0));
-
-  EXPECT_EQ(
-      Expression::CreateLogicalFunctionCall("isfinite", {ExpressionId(3)}),
-      Expression(ExpressionType::FUNCTION_CALL,
-                 ExpressionReturnType::BOOLEAN,
-                 kInvalidExpressionId,
-                 {3},
-                 "isfinite",
-                 0));
-
-  EXPECT_EQ(Expression::CreateIf(ExpressionId(5)),
-            Expression(ExpressionType::IF,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {5},
-                       "",
-                       0));
-
-  EXPECT_EQ(Expression::CreateElse(),
-            Expression(ExpressionType::ELSE,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {},
-                       "",
-                       0));
-
-  EXPECT_EQ(Expression::CreateEndIf(),
-            Expression(ExpressionType::ENDIF,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {},
-                       "",
-                       0));
-
-  EXPECT_EQ(Expression::CreateComment("Test"),
-            Expression(ExpressionType::COMMENT,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {},
-                       "Test",
-                       0));
-}
-
-TEST(Expression, IsArithmeticExpression) {
-  ASSERT_TRUE(
-      Expression::CreateCompileTimeConstant(5).IsArithmeticExpression());
-  ASSERT_TRUE(Expression::CreateScalarFunctionCall("pow", {3, 5})
-                  .IsArithmeticExpression());
-  // Logical expression are also arithmetic!
-  ASSERT_TRUE(
-      Expression::CreateBinaryCompare("<", 3, 5).IsArithmeticExpression());
-  ASSERT_FALSE(Expression::CreateIf(5).IsArithmeticExpression());
-  ASSERT_FALSE(Expression::CreateEndIf().IsArithmeticExpression());
-  ASSERT_FALSE(Expression().IsArithmeticExpression());
-}
-
-TEST(Expression, IsControlExpression) {
-  // In the current implementation this is the exact opposite of
-  // IsArithmeticExpression.
-  ASSERT_FALSE(Expression::CreateCompileTimeConstant(5).IsControlExpression());
-  ASSERT_FALSE(Expression::CreateScalarFunctionCall("pow", {3, 5})
-                   .IsControlExpression());
-  ASSERT_FALSE(
-      Expression::CreateBinaryCompare("<", 3, 5).IsControlExpression());
-  ASSERT_TRUE(Expression::CreateIf(5).IsControlExpression());
-  ASSERT_TRUE(Expression::CreateEndIf().IsControlExpression());
-  ASSERT_TRUE(Expression::CreateComment("Test").IsControlExpression());
-  ASSERT_TRUE(Expression().IsControlExpression());
-}
-
-TEST(Expression, IsCompileTimeConstantAndEqualTo) {
-  ASSERT_TRUE(
-      Expression::CreateCompileTimeConstant(5).IsCompileTimeConstantAndEqualTo(
-          5));
-  ASSERT_FALSE(
-      Expression::CreateCompileTimeConstant(3).IsCompileTimeConstantAndEqualTo(
-          5));
-  ASSERT_FALSE(Expression::CreateBinaryCompare("<", 3, 5)
-                   .IsCompileTimeConstantAndEqualTo(5));
-}
-
-TEST(Expression, IsReplaceableBy) {
-  // Create 2 identical expression
-  auto expr1 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  auto expr2 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  // They are idendical and of course replaceable
-  ASSERT_EQ(expr1, expr2);
-  ASSERT_EQ(expr2, expr1);
-  ASSERT_TRUE(expr1.IsReplaceableBy(expr2));
-  ASSERT_TRUE(expr2.IsReplaceableBy(expr1));
-
-  // Give them different left hand sides
-  expr1.set_lhs_id(72);
-  expr2.set_lhs_id(42);
-
-  // v_72 = v_3 + v_5
-  // v_42 = v_3 + v_5
-  // -> They should be replaceable by each other
-
-  ASSERT_NE(expr1, expr2);
-  ASSERT_NE(expr2, expr1);
-
-  ASSERT_TRUE(expr1.IsReplaceableBy(expr2));
-  ASSERT_TRUE(expr2.IsReplaceableBy(expr1));
-
-  // A slightly differnt expression with the argument flipped
-  auto expr3 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(5), ExpressionId(3));
-
-  ASSERT_NE(expr1, expr3);
-  ASSERT_FALSE(expr1.IsReplaceableBy(expr3));
-}
-
-TEST(Expression, Replace) {
-  auto expr1 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-  expr1.set_lhs_id(13);
-
-  auto expr2 =
-      Expression::CreateAssignment(kInvalidExpressionId, ExpressionId(7));
-
-  // We replace the arithmetic expr1 by an assignment from the variable 7. This
-  // is the typical usecase in subexpression elimination.
-  expr1.Replace(expr2);
-
-  // expr1 should now be an assignment from 7 to 13
-  EXPECT_EQ(expr1,
-            Expression(ExpressionType::ASSIGNMENT,
-                       ExpressionReturnType::SCALAR,
-                       13,
-                       {7},
-                       "",
-                       0));
-}
-
-TEST(Expression, DirectlyDependsOn) {
-  auto expr1 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  ASSERT_TRUE(expr1.DirectlyDependsOn(ExpressionId(3)));
-  ASSERT_TRUE(expr1.DirectlyDependsOn(ExpressionId(5)));
-  ASSERT_FALSE(expr1.DirectlyDependsOn(ExpressionId(kInvalidExpressionId)));
-  ASSERT_FALSE(expr1.DirectlyDependsOn(ExpressionId(42)));
-}
-TEST(Expression, MakeNop) {
-  auto expr1 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  expr1.MakeNop();
-
-  EXPECT_EQ(expr1,
-            Expression(ExpressionType::NOP,
-                       ExpressionReturnType::VOID,
-                       kInvalidExpressionId,
-                       {},
-                       "",
-                       0));
-}
-
-TEST(Expression, IsSemanticallyEquivalentTo) {
-  // Create 2 identical expression
-  auto expr1 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  auto expr2 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(5));
-
-  ASSERT_TRUE(expr1.IsSemanticallyEquivalentTo(expr1));
-  ASSERT_TRUE(expr1.IsSemanticallyEquivalentTo(expr2));
-
-  auto expr3 =
-      Expression::CreateBinaryArithmetic("+", ExpressionId(3), ExpressionId(8));
-
-  ASSERT_TRUE(expr1.IsSemanticallyEquivalentTo(expr3));
-
-  auto expr4 =
-      Expression::CreateBinaryArithmetic("-", ExpressionId(3), ExpressionId(5));
-
-  ASSERT_FALSE(expr1.IsSemanticallyEquivalentTo(expr4));
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/test_utils.cc b/internal/ceres/codegen/test_utils.cc
deleted file mode 100644
index 303c0db..0000000
--- a/internal/ceres/codegen/test_utils.cc
+++ /dev/null
@@ -1,88 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2020 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-
-#include "ceres/codegen/test_utils.h"
-#include "ceres/test_util.h"
-
-namespace ceres {
-namespace internal {
-
-std::pair<std::vector<double>, std::vector<double> > EvaluateCostFunction(
-    CostFunction* cost_function, double value) {
-  auto num_residuals = cost_function->num_residuals();
-  auto parameter_block_sizes = cost_function->parameter_block_sizes();
-  auto num_parameter_blocks = parameter_block_sizes.size();
-
-  int total_num_parameters = 0;
-  for (auto block_size : parameter_block_sizes) {
-    total_num_parameters += block_size;
-  }
-
-  std::vector<double> params_array(total_num_parameters, value);
-  std::vector<double*> params(num_parameter_blocks);
-  std::vector<double> residuals(num_residuals, 0);
-  std::vector<double> jacobians_array(num_residuals * total_num_parameters, 0);
-  std::vector<double*> jacobians(num_parameter_blocks);
-
-  for (int i = 0, k = 0; i < num_parameter_blocks;
-       k += parameter_block_sizes[i], ++i) {
-    params[i] = &params_array[k];
-  }
-
-  for (int i = 0, k = 0; i < num_parameter_blocks;
-       k += parameter_block_sizes[i], ++i) {
-    jacobians[i] = &jacobians_array[k * num_residuals];
-  }
-
-  cost_function->Evaluate(params.data(), residuals.data(), jacobians.data());
-
-  return std::make_pair(residuals, jacobians_array);
-}
-
-void CompareCostFunctions(CostFunction* cost_function1,
-                          CostFunction* cost_function2,
-
-                          double value,
-                          double tol) {
-  auto residuals_and_jacobians_1 = EvaluateCostFunction(cost_function1, value);
-  auto residuals_and_jacobians_2 = EvaluateCostFunction(cost_function2, value);
-
-  ExpectArraysClose(residuals_and_jacobians_1.first.size(),
-                    residuals_and_jacobians_1.first.data(),
-                    residuals_and_jacobians_2.first.data(),
-                    tol);
-  ExpectArraysClose(residuals_and_jacobians_1.second.size(),
-                    residuals_and_jacobians_1.second.data(),
-                    residuals_and_jacobians_2.second.data(),
-                    tol);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/codegen/test_utils.h b/internal/ceres/codegen/test_utils.h
deleted file mode 100644
index eaaf438..0000000
--- a/internal/ceres/codegen/test_utils.h
+++ /dev/null
@@ -1,82 +0,0 @@
-// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2020 Google Inc. All rights reserved.
-// http://code.google.com/p/ceres-solver/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are met:
-//
-// * Redistributions of source code must retain the above copyright notice,
-//   this list of conditions and the following disclaimer.
-// * Redistributions in binary form must reproduce the above copyright notice,
-//   this list of conditions and the following disclaimer in the documentation
-//   and/or other materials provided with the distribution.
-// * Neither the name of Google Inc. nor the names of its contributors may be
-//   used to endorse or promote products derived from this software without
-//   specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-// POSSIBILITY OF SUCH DAMAGE.
-//
-// Author: darius.rueckert@fau.de (Darius Rueckert)
-
-#ifndef CERES_INTERNAL_CODEGEN_TEST_UTILS_H_
-#define CERES_INTERNAL_CODEGEN_TEST_UTILS_H_
-
-#include "ceres/internal/autodiff.h"
-#include "ceres/random.h"
-#include "ceres/sized_cost_function.h"
-
-namespace ceres {
-namespace internal {
-
-// CodegenCostFunctions have both, an templated operator() and the Evaluate()
-// function. The operator() is used during code generation and Evaluate() is
-// used during execution.
-//
-// If we want to use the operator() during execution (with autodiff) this
-// wrapper class here has to be used. Autodiff doesn't support functors that
-// have an Evaluate() function.
-//
-// CostFunctionToFunctor hides the Evaluate() function, because it doesn't
-// derive from CostFunction. Autodiff sees it as a simple functor and will use
-// the operator() as expected.
-template <typename CostFunction>
-struct CostFunctionToFunctor {
-  template <typename... _Args>
-  CostFunctionToFunctor(_Args&&... __args)
-      : cost_function(std::forward<_Args>(__args)...) {}
-
-  template <typename... _Args>
-  bool operator()(_Args&&... __args) const {
-    return cost_function(std::forward<_Args>(__args)...);
-  }
-
-  CostFunction cost_function;
-};
-
-// Evaluate a cost function and return the residuals and jacobians.
-// All parameters are set to 'value'.
-std::pair<std::vector<double>, std::vector<double>> EvaluateCostFunction(
-    CostFunction* cost_function, double value);
-
-// Evaluates the two cost functions using the method above and then compares the
-// result. The comparison uses GTEST expect macros so this function should be
-// called from a test enviroment.
-void CompareCostFunctions(CostFunction* cost_function1,
-                          CostFunction* cost_function2,
-                          double value,
-                          double tol);
-
-}  // namespace internal
-}  // namespace ceres
-
-#endif