Remove remaining references to CXSparse

Also remove examples/Makefile.example as it is hopelessly
out of date.

Change-Id: I2ed2f0c4768eacbf65cf76299c7a8b3474eb750b
diff --git a/examples/Makefile.example b/examples/Makefile.example
deleted file mode 100644
index f2b0dc0..0000000
--- a/examples/Makefile.example
+++ /dev/null
@@ -1,82 +0,0 @@
-# Ceres Solver - A fast non-linear least squares minimizer
-# Copyright 2015 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: keir@google.com (Keir Mierle)
-#
-# This is an example Makefile for using Ceres. In practice, the Ceres authors
-# suggest using CMake instead, but if Make is needed for some reason, this
-# example serves to make it easy to do so.
-
-# This should point to place where you unpacked or cloned Ceres.
-CERES_SRC_DIR := /home/keir/wrk/ceres-extra
-
-# This should point to the place where you built Ceres. If you got Ceres by
-# installing it, then this will likely be /usr/local/lib.
-CERES_BIN_DIR := /home/keir/wrk/ceres-extra-bin
-
-# The place you unpacked or cloned Eigen. If Eigen was installed from packages,
-# this will likely be /usr/local/include.
-EIGEN_SRC_DIR := /home/keir/src/eigen-3.0.5
-
-INCLUDES := -I$(CERES_SRC_DIR)/include \
-            -I$(EIGEN_SRC_DIR)
-
-CERES_LIBRARY := -lceres
-CERES_LIBRARY_PATH := -L$(CERES_BIN_DIR)/lib
-CERES_LIBRARY_DEPENDENCIES = -lgflags -lglog
-
-# If Ceres was built with Suitesparse:
-CERES_LIBRARY_DEPENDENCIES += -llapack -lcamd -lamd -lccolamd -lcolamd -lcholmod
-
-# If Ceres was built with CXSparse:
-CERES_LIBRARY_DEPENDENCIES += -lcxsparse
-
-# If Ceres was built with OpenMP:
-CERES_LIBRARY_DEPENDENCIES += -fopenmp -lpthread -lgomp -lm
-
-# The set of object files for your application.
-APPLICATION_OBJS := simple_bundle_adjuster.o
-
-all: simple_bundle_adjuster
-
-simple_bundle_adjuster: $(APPLICATION_OBJS)
-	g++ \
-		$(APPLICATION_OBJS) \
-		$(CERES_LIBRARY_PATH) \
-		$(CERES_LIBRARY) \
-		$(CERES_LIBRARY_DEPENDENCIES) \
-		-o simple_bundle_adjuster
-
-# Disabling debug asserts via -DNDEBUG helps make Eigen faster, at the cost of
-# not getting handy assert failures when there are issues in your code.
-CFLAGS := -O2 -DNDEBUG
-
-# If you have files ending in .cpp instead of .cc, fix the next line
-# appropriately.
-%.o: %.cc $(DEPS)
-	g++ -c -o $@ $< $(CFLAGS) $(INCLUDES)
diff --git a/internal/ceres/dynamic_sparse_normal_cholesky_solver.h b/internal/ceres/dynamic_sparse_normal_cholesky_solver.h
index 022b38e..394ba2a 100644
--- a/internal/ceres/dynamic_sparse_normal_cholesky_solver.h
+++ b/internal/ceres/dynamic_sparse_normal_cholesky_solver.h
@@ -67,9 +67,6 @@
   LinearSolver::Summary SolveImplUsingSuiteSparse(CompressedRowSparseMatrix* A,
                                                   double* rhs_and_solution);
 
-  LinearSolver::Summary SolveImplUsingCXSparse(CompressedRowSparseMatrix* A,
-                                               double* rhs_and_solution);
-
   LinearSolver::Summary SolveImplUsingEigen(CompressedRowSparseMatrix* A,
                                             double* rhs_and_solution);
 
diff --git a/internal/ceres/problem_impl.cc b/internal/ceres/problem_impl.cc
index 0a6b446..52575ee 100644
--- a/internal/ceres/problem_impl.cc
+++ b/internal/ceres/problem_impl.cc
@@ -667,11 +667,11 @@
 
   Evaluator::Options evaluator_options;
 
-  // Even though using SPARSE_NORMAL_CHOLESKY requires SuiteSparse or
-  // CXSparse, here it just being used for telling the evaluator to
-  // use a SparseRowCompressedMatrix for the jacobian. This is because
-  // the Evaluator decides the storage for the Jacobian based on the
-  // type of linear solver being used.
+  // Even though using SPARSE_NORMAL_CHOLESKY requires a sparse linear algebra
+  // library here it just being used for telling the evaluator to use a
+  // SparseRowCompressedMatrix for the jacobian. This is because the Evaluator
+  // decides the storage for the Jacobian based on the type of linear solver
+  // being used.
   evaluator_options.linear_solver_type = SPARSE_NORMAL_CHOLESKY;
   evaluator_options.num_threads = evaluate_options.num_threads;