diff --git a/internal/ceres/conditioned_cost_function.cc b/internal/ceres/conditioned_cost_function.cc
new file mode 100644
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+++ b/internal/ceres/conditioned_cost_function.cc
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2010, 2011, 2012 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: wjr@google.com (William Rucklidge)
+//
+// This file contains the implementation of the conditioned cost function.
+
+#include "ceres/conditioned_cost_function.h"
+
+#include <cstddef>
+
+#include <glog/logging.h>
+#include "ceres/stl_util.h"
+#include "ceres/internal/eigen.h"
+#include "ceres/types.h"
+
+namespace ceres {
+
+// This cost function has the same dimensions (parameters, residuals) as
+// the one it's wrapping.
+ConditionedCostFunction::ConditionedCostFunction(
+    CostFunction* wrapped_cost_function,
+    const vector<CostFunction*>& conditioners,
+    Ownership ownership)
+    : wrapped_cost_function_(wrapped_cost_function),
+      conditioners_(conditioners),
+      ownership_(ownership) {
+  // Set up our dimensions.
+  set_num_residuals(wrapped_cost_function_->num_residuals());
+  *mutable_parameter_block_sizes() =
+      wrapped_cost_function_->parameter_block_sizes();
+
+  // Sanity-check the conditioners' dimensions.
+  CHECK_EQ(wrapped_cost_function_->num_residuals(), conditioners_.size());
+  for (int i = 0; i < wrapped_cost_function_->num_residuals(); i++) {
+    if (conditioners[i]) {
+      CHECK_EQ(1, conditioners[i]->num_residuals());
+      CHECK_EQ(1, conditioners[i]->parameter_block_sizes().size());
+      CHECK_EQ(1, conditioners[i]->parameter_block_sizes()[0]);
+    }
+  }
+}
+
+ConditionedCostFunction::~ConditionedCostFunction() {
+  if (ownership_ == TAKE_OWNERSHIP) {
+    STLDeleteElements(&conditioners_);
+  } else {
+    wrapped_cost_function_.release();
+  }
+}
+
+bool ConditionedCostFunction::Evaluate(double const* const* parameters,
+                                       double* residuals,
+                                       double** jacobians) const {
+  bool success = wrapped_cost_function_->Evaluate(parameters, residuals,
+                                                  jacobians);
+  if (!success) {
+    return false;
+  }
+
+  for (int r = 0; r < wrapped_cost_function_->num_residuals(); r++) {
+    // On output, we want to have
+    // residuals[r] = conditioners[r](wrapped_residuals[r])
+    // For parameter block i, column c,
+    // jacobians[i][r*parameter_block_size_[i] + c] =
+    //   = d residual[r] / d parameters[i][c]
+    //   = conditioners[r]'(wrapped_residuals[r]) *
+    //       d wrapped_residuals[r] / d parameters[i][c]
+    if (conditioners_[r]) {
+      double conditioner_derivative;
+      double* conditioner_derivative_pointer = &conditioner_derivative;
+      double** conditioner_derivative_pointer2 =
+          &conditioner_derivative_pointer;
+      if (!jacobians) {
+        conditioner_derivative_pointer2 = NULL;
+      }
+
+      double unconditioned_residual = residuals[r];
+      double* parameter_pointer = &unconditioned_residual;
+      success = conditioners_[r]->Evaluate(&parameter_pointer,
+                                           &residuals[r],
+                                           conditioner_derivative_pointer2);
+      if (!success) {
+        return false;
+      }
+
+      if (jacobians) {
+        for (int i = 0;
+             i < wrapped_cost_function_->parameter_block_sizes().size();
+             i++) {
+          if (jacobians[i]) {
+            int parameter_block_size =
+                wrapped_cost_function_->parameter_block_sizes()[i];
+            VectorRef jacobian_row(jacobians[i] + r * parameter_block_size,
+                                   parameter_block_size, 1);
+            jacobian_row *= conditioner_derivative;
+          }
+        }
+      }
+    }
+  }
+  return true;
+}
+
+}  // namespace ceres