Squashed 'third_party/ceres/' content from commit e51e9b4

Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/internal/ceres/solver.cc b/internal/ceres/solver.cc
new file mode 100644
index 0000000..f8ad2c9
--- /dev/null
+++ b/internal/ceres/solver.cc
@@ -0,0 +1,838 @@
+// 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)
+//         sameeragarwal@google.com (Sameer Agarwal)
+
+#include "ceres/solver.h"
+
+#include <algorithm>
+#include <memory>
+#include <sstream>  // NOLINT
+#include <vector>
+
+#include "ceres/casts.h"
+#include "ceres/context.h"
+#include "ceres/context_impl.h"
+#include "ceres/detect_structure.h"
+#include "ceres/gradient_checking_cost_function.h"
+#include "ceres/internal/port.h"
+#include "ceres/parameter_block_ordering.h"
+#include "ceres/preprocessor.h"
+#include "ceres/problem.h"
+#include "ceres/problem_impl.h"
+#include "ceres/program.h"
+#include "ceres/schur_templates.h"
+#include "ceres/solver_utils.h"
+#include "ceres/stringprintf.h"
+#include "ceres/types.h"
+#include "ceres/wall_time.h"
+
+namespace ceres {
+namespace {
+
+using std::map;
+using std::string;
+using std::vector;
+using internal::StringAppendF;
+using internal::StringPrintf;
+
+#define OPTION_OP(x, y, OP)                                             \
+  if (!(options.x OP y)) {                                              \
+    std::stringstream ss;                                               \
+    ss << "Invalid configuration. ";                                    \
+    ss << string("Solver::Options::" #x " = ") << options.x << ". ";    \
+    ss << "Violated constraint: ";                                      \
+    ss << string("Solver::Options::" #x " " #OP " "#y);                 \
+    *error = ss.str();                                                  \
+    return false;                                                       \
+  }
+
+#define OPTION_OP_OPTION(x, y, OP)                                      \
+  if (!(options.x OP options.y)) {                                      \
+    std::stringstream ss;                                               \
+    ss << "Invalid configuration. ";                                    \
+    ss << string("Solver::Options::" #x " = ") << options.x << ". ";    \
+    ss << string("Solver::Options::" #y " = ") << options.y << ". ";    \
+    ss << "Violated constraint: ";                                      \
+    ss << string("Solver::Options::" #x);                               \
+    ss << string(#OP " Solver::Options::" #y ".");                      \
+    *error = ss.str();                                                  \
+    return false;                                                       \
+  }
+
+#define OPTION_GE(x, y) OPTION_OP(x, y, >=);
+#define OPTION_GT(x, y) OPTION_OP(x, y, >);
+#define OPTION_LE(x, y) OPTION_OP(x, y, <=);
+#define OPTION_LT(x, y) OPTION_OP(x, y, <);
+#define OPTION_LE_OPTION(x, y) OPTION_OP_OPTION(x, y, <=)
+#define OPTION_LT_OPTION(x, y) OPTION_OP_OPTION(x, y, <)
+
+bool CommonOptionsAreValid(const Solver::Options& options, string* error) {
+  OPTION_GE(max_num_iterations, 0);
+  OPTION_GE(max_solver_time_in_seconds, 0.0);
+  OPTION_GE(function_tolerance, 0.0);
+  OPTION_GE(gradient_tolerance, 0.0);
+  OPTION_GE(parameter_tolerance, 0.0);
+  OPTION_GT(num_threads, 0);
+  if (options.check_gradients) {
+    OPTION_GT(gradient_check_relative_precision, 0.0);
+    OPTION_GT(gradient_check_numeric_derivative_relative_step_size, 0.0);
+  }
+  return true;
+}
+
+bool TrustRegionOptionsAreValid(const Solver::Options& options, string* error) {
+  OPTION_GT(initial_trust_region_radius, 0.0);
+  OPTION_GT(min_trust_region_radius, 0.0);
+  OPTION_GT(max_trust_region_radius, 0.0);
+  OPTION_LE_OPTION(min_trust_region_radius, max_trust_region_radius);
+  OPTION_LE_OPTION(min_trust_region_radius, initial_trust_region_radius);
+  OPTION_LE_OPTION(initial_trust_region_radius, max_trust_region_radius);
+  OPTION_GE(min_relative_decrease, 0.0);
+  OPTION_GE(min_lm_diagonal, 0.0);
+  OPTION_GE(max_lm_diagonal, 0.0);
+  OPTION_LE_OPTION(min_lm_diagonal, max_lm_diagonal);
+  OPTION_GE(max_num_consecutive_invalid_steps, 0);
+  OPTION_GT(eta, 0.0);
+  OPTION_GE(min_linear_solver_iterations, 0);
+  OPTION_GE(max_linear_solver_iterations, 1);
+  OPTION_LE_OPTION(min_linear_solver_iterations, max_linear_solver_iterations);
+
+  if (options.use_inner_iterations) {
+    OPTION_GE(inner_iteration_tolerance, 0.0);
+  }
+
+  if (options.use_inner_iterations &&
+      options.evaluation_callback != NULL) {
+    *error =  "Inner iterations (use_inner_iterations = true) can't be "
+        "combined with an evaluation callback "
+        "(options.evaluation_callback != NULL).";
+    return false;
+  }
+
+  if (options.use_nonmonotonic_steps) {
+    OPTION_GT(max_consecutive_nonmonotonic_steps, 0);
+  }
+
+  if (options.linear_solver_type == ITERATIVE_SCHUR &&
+      options.use_explicit_schur_complement &&
+      options.preconditioner_type != SCHUR_JACOBI) {
+    *error =  "use_explicit_schur_complement only supports "
+        "SCHUR_JACOBI as the preconditioner.";
+    return false;
+  }
+
+  if (options.dense_linear_algebra_library_type == LAPACK &&
+      !IsDenseLinearAlgebraLibraryTypeAvailable(LAPACK) &&
+      (options.linear_solver_type == DENSE_NORMAL_CHOLESKY ||
+       options.linear_solver_type == DENSE_QR ||
+       options.linear_solver_type == DENSE_SCHUR)) {
+    *error = StringPrintf(
+        "Can't use %s with "
+        "Solver::Options::dense_linear_algebra_library_type = LAPACK "
+        "because LAPACK was not enabled when Ceres was built.",
+        LinearSolverTypeToString(options.linear_solver_type));
+    return false;
+  }
+
+  if (options.sparse_linear_algebra_library_type == NO_SPARSE) {
+    const char* error_template =
+        "Can't use %s with "
+        "Solver::Options::sparse_linear_algebra_library_type = NO_SPARSE.";
+    const char* name = nullptr;
+
+    if (options.linear_solver_type == SPARSE_NORMAL_CHOLESKY ||
+        options.linear_solver_type == SPARSE_SCHUR) {
+      name = LinearSolverTypeToString(options.linear_solver_type);
+    } else if (options.linear_solver_type == ITERATIVE_SCHUR &&
+               (options.preconditioner_type == CLUSTER_JACOBI ||
+                options.preconditioner_type == CLUSTER_TRIDIAGONAL)) {
+      name = PreconditionerTypeToString(options.preconditioner_type);
+    }
+
+    if (name != nullptr) {
+      *error = StringPrintf(error_template, name);
+      return false;
+    }
+  } else if (!IsSparseLinearAlgebraLibraryTypeAvailable(
+                 options.sparse_linear_algebra_library_type)) {
+    const char* error_template =
+        "Can't use %s with "
+        "Solver::Options::sparse_linear_algebra_library_type = %s, "
+        "because support was not enabled when Ceres Solver was built.";
+    const char* name = nullptr;
+    if (options.linear_solver_type == SPARSE_NORMAL_CHOLESKY ||
+        options.linear_solver_type == SPARSE_SCHUR) {
+      name = LinearSolverTypeToString(options.linear_solver_type);
+    } else if (options.linear_solver_type == ITERATIVE_SCHUR &&
+               (options.preconditioner_type == CLUSTER_JACOBI ||
+                options.preconditioner_type == CLUSTER_TRIDIAGONAL)) {
+      name = PreconditionerTypeToString(options.preconditioner_type);
+    }
+
+    if (name != nullptr) {
+      *error = StringPrintf(error_template,
+                            name,
+                            SparseLinearAlgebraLibraryTypeToString(
+                                options.sparse_linear_algebra_library_type));
+      return false;
+    }
+  }
+
+  if (options.trust_region_strategy_type == DOGLEG) {
+    if (options.linear_solver_type == ITERATIVE_SCHUR ||
+        options.linear_solver_type == CGNR) {
+      *error = "DOGLEG only supports exact factorization based linear "
+          "solvers. If you want to use an iterative solver please "
+          "use LEVENBERG_MARQUARDT as the trust_region_strategy_type";
+      return false;
+    }
+  }
+
+  if (options.trust_region_minimizer_iterations_to_dump.size() > 0 &&
+      options.trust_region_problem_dump_format_type != CONSOLE &&
+      options.trust_region_problem_dump_directory.empty()) {
+    *error = "Solver::Options::trust_region_problem_dump_directory is empty.";
+    return false;
+  }
+
+  if (options.dynamic_sparsity &&
+      options.linear_solver_type != SPARSE_NORMAL_CHOLESKY) {
+    *error = "Dynamic sparsity is only supported with SPARSE_NORMAL_CHOLESKY.";
+    return false;
+  }
+
+  return true;
+}
+
+bool LineSearchOptionsAreValid(const Solver::Options& options, string* error) {
+  OPTION_GT(max_lbfgs_rank, 0);
+  OPTION_GT(min_line_search_step_size, 0.0);
+  OPTION_GT(max_line_search_step_contraction, 0.0);
+  OPTION_LT(max_line_search_step_contraction, 1.0);
+  OPTION_LT_OPTION(max_line_search_step_contraction,
+                   min_line_search_step_contraction);
+  OPTION_LE(min_line_search_step_contraction, 1.0);
+  OPTION_GT(max_num_line_search_step_size_iterations, 0);
+  OPTION_GT(line_search_sufficient_function_decrease, 0.0);
+  OPTION_LT_OPTION(line_search_sufficient_function_decrease,
+                   line_search_sufficient_curvature_decrease);
+  OPTION_LT(line_search_sufficient_curvature_decrease, 1.0);
+  OPTION_GT(max_line_search_step_expansion, 1.0);
+
+  if ((options.line_search_direction_type == ceres::BFGS ||
+       options.line_search_direction_type == ceres::LBFGS) &&
+      options.line_search_type != ceres::WOLFE) {
+    *error =
+        string("Invalid configuration: Solver::Options::line_search_type = ")
+        + string(LineSearchTypeToString(options.line_search_type))
+        + string(". When using (L)BFGS, "
+                 "Solver::Options::line_search_type must be set to WOLFE.");
+    return false;
+  }
+
+  // Warn user if they have requested BISECTION interpolation, but constraints
+  // on max/min step size change during line search prevent bisection scaling
+  // from occurring. Warn only, as this is likely a user mistake, but one which
+  // does not prevent us from continuing.
+  LOG_IF(WARNING,
+         (options.line_search_interpolation_type == ceres::BISECTION &&
+          (options.max_line_search_step_contraction > 0.5 ||
+           options.min_line_search_step_contraction < 0.5)))
+      << "Line search interpolation type is BISECTION, but specified "
+      << "max_line_search_step_contraction: "
+      << options.max_line_search_step_contraction << ", and "
+      << "min_line_search_step_contraction: "
+      << options.min_line_search_step_contraction
+      << ", prevent bisection (0.5) scaling, continuing with solve regardless.";
+
+  return true;
+}
+
+#undef OPTION_OP
+#undef OPTION_OP_OPTION
+#undef OPTION_GT
+#undef OPTION_GE
+#undef OPTION_LE
+#undef OPTION_LT
+#undef OPTION_LE_OPTION
+#undef OPTION_LT_OPTION
+
+void StringifyOrdering(const vector<int>& ordering, string* report) {
+  if (ordering.size() == 0) {
+    internal::StringAppendF(report, "AUTOMATIC");
+    return;
+  }
+
+  for (int i = 0; i < ordering.size() - 1; ++i) {
+    internal::StringAppendF(report, "%d,", ordering[i]);
+  }
+  internal::StringAppendF(report, "%d", ordering.back());
+}
+
+void SummarizeGivenProgram(const internal::Program& program,
+                           Solver::Summary* summary) {
+  summary->num_parameter_blocks     = program.NumParameterBlocks();
+  summary->num_parameters           = program.NumParameters();
+  summary->num_effective_parameters = program.NumEffectiveParameters();
+  summary->num_residual_blocks      = program.NumResidualBlocks();
+  summary->num_residuals            = program.NumResiduals();
+}
+
+void SummarizeReducedProgram(const internal::Program& program,
+                             Solver::Summary* summary) {
+  summary->num_parameter_blocks_reduced     = program.NumParameterBlocks();
+  summary->num_parameters_reduced           = program.NumParameters();
+  summary->num_effective_parameters_reduced = program.NumEffectiveParameters();
+  summary->num_residual_blocks_reduced      = program.NumResidualBlocks();
+  summary->num_residuals_reduced            = program.NumResiduals();
+}
+
+void PreSolveSummarize(const Solver::Options& options,
+                       const internal::ProblemImpl* problem,
+                       Solver::Summary* summary) {
+  SummarizeGivenProgram(problem->program(), summary);
+  internal::OrderingToGroupSizes(options.linear_solver_ordering.get(),
+                                 &(summary->linear_solver_ordering_given));
+  internal::OrderingToGroupSizes(options.inner_iteration_ordering.get(),
+                                 &(summary->inner_iteration_ordering_given));
+
+  summary->dense_linear_algebra_library_type  = options.dense_linear_algebra_library_type;  //  NOLINT
+  summary->dogleg_type                        = options.dogleg_type;
+  summary->inner_iteration_time_in_seconds    = 0.0;
+  summary->num_line_search_steps              = 0;
+  summary->line_search_cost_evaluation_time_in_seconds = 0.0;
+  summary->line_search_gradient_evaluation_time_in_seconds = 0.0;
+  summary->line_search_polynomial_minimization_time_in_seconds = 0.0;
+  summary->line_search_total_time_in_seconds  = 0.0;
+  summary->inner_iterations_given             = options.use_inner_iterations;
+  summary->line_search_direction_type         = options.line_search_direction_type;         //  NOLINT
+  summary->line_search_interpolation_type     = options.line_search_interpolation_type;     //  NOLINT
+  summary->line_search_type                   = options.line_search_type;
+  summary->linear_solver_type_given           = options.linear_solver_type;
+  summary->max_lbfgs_rank                     = options.max_lbfgs_rank;
+  summary->minimizer_type                     = options.minimizer_type;
+  summary->nonlinear_conjugate_gradient_type  = options.nonlinear_conjugate_gradient_type;  //  NOLINT
+  summary->num_threads_given                  = options.num_threads;
+  summary->preconditioner_type_given          = options.preconditioner_type;
+  summary->sparse_linear_algebra_library_type = options.sparse_linear_algebra_library_type; //  NOLINT
+  summary->trust_region_strategy_type         = options.trust_region_strategy_type;         //  NOLINT
+  summary->visibility_clustering_type         = options.visibility_clustering_type;         //  NOLINT
+}
+
+void PostSolveSummarize(const internal::PreprocessedProblem& pp,
+                        Solver::Summary* summary) {
+  internal::OrderingToGroupSizes(pp.options.linear_solver_ordering.get(),
+                                 &(summary->linear_solver_ordering_used));
+  internal::OrderingToGroupSizes(pp.options.inner_iteration_ordering.get(),
+                                 &(summary->inner_iteration_ordering_used));
+
+  summary->inner_iterations_used          = pp.inner_iteration_minimizer.get() != NULL;     // NOLINT
+  summary->linear_solver_type_used        = pp.linear_solver_options.type;
+  summary->num_threads_used               = pp.options.num_threads;
+  summary->preconditioner_type_used       = pp.options.preconditioner_type;
+
+  internal::SetSummaryFinalCost(summary);
+
+  if (pp.reduced_program.get() != NULL) {
+    SummarizeReducedProgram(*pp.reduced_program, summary);
+  }
+
+  using internal::CallStatistics;
+
+  // It is possible that no evaluator was created. This would be the
+  // case if the preprocessor failed, or if the reduced problem did
+  // not contain any parameter blocks. Thus, only extract the
+  // evaluator statistics if one exists.
+  if (pp.evaluator.get() != NULL) {
+    const map<string, CallStatistics>& evaluator_statistics =
+        pp.evaluator->Statistics();
+    {
+      const CallStatistics& call_stats = FindWithDefault(
+          evaluator_statistics, "Evaluator::Residual", CallStatistics());
+
+      summary->residual_evaluation_time_in_seconds = call_stats.time;
+      summary->num_residual_evaluations = call_stats.calls;
+    }
+    {
+      const CallStatistics& call_stats = FindWithDefault(
+          evaluator_statistics, "Evaluator::Jacobian", CallStatistics());
+
+      summary->jacobian_evaluation_time_in_seconds = call_stats.time;
+      summary->num_jacobian_evaluations = call_stats.calls;
+    }
+  }
+
+  // Again, like the evaluator, there may or may not be a linear
+  // solver from which we can extract run time statistics. In
+  // particular the line search solver does not use a linear solver.
+  if (pp.linear_solver.get() != NULL) {
+    const map<string, CallStatistics>& linear_solver_statistics =
+        pp.linear_solver->Statistics();
+    const CallStatistics& call_stats = FindWithDefault(
+        linear_solver_statistics, "LinearSolver::Solve", CallStatistics());
+    summary->num_linear_solves = call_stats.calls;
+    summary->linear_solver_time_in_seconds = call_stats.time;
+  }
+}
+
+void Minimize(internal::PreprocessedProblem* pp,
+              Solver::Summary* summary) {
+  using internal::Program;
+  using internal::Minimizer;
+
+  Program* program = pp->reduced_program.get();
+  if (pp->reduced_program->NumParameterBlocks() == 0) {
+    summary->message = "Function tolerance reached. "
+        "No non-constant parameter blocks found.";
+    summary->termination_type = CONVERGENCE;
+    VLOG_IF(1, pp->options.logging_type != SILENT) << summary->message;
+    summary->initial_cost = summary->fixed_cost;
+    summary->final_cost = summary->fixed_cost;
+    return;
+  }
+
+  const Vector original_reduced_parameters = pp->reduced_parameters;
+  std::unique_ptr<Minimizer> minimizer(
+      Minimizer::Create(pp->options.minimizer_type));
+  minimizer->Minimize(pp->minimizer_options,
+                      pp->reduced_parameters.data(),
+                      summary);
+
+  program->StateVectorToParameterBlocks(
+      summary->IsSolutionUsable()
+      ? pp->reduced_parameters.data()
+      : original_reduced_parameters.data());
+  program->CopyParameterBlockStateToUserState();
+}
+
+std::string SchurStructureToString(const int row_block_size,
+                                   const int e_block_size,
+                                   const int f_block_size) {
+  const std::string row =
+      (row_block_size == Eigen::Dynamic)
+      ? "d" : internal::StringPrintf("%d", row_block_size);
+
+  const std::string e =
+      (e_block_size == Eigen::Dynamic)
+      ? "d" : internal::StringPrintf("%d", e_block_size);
+
+  const std::string f =
+      (f_block_size == Eigen::Dynamic)
+      ? "d" : internal::StringPrintf("%d", f_block_size);
+
+  return internal::StringPrintf("%s,%s,%s", row.c_str(), e.c_str(), f.c_str());
+}
+
+}  // namespace
+
+bool Solver::Options::IsValid(string* error) const {
+  if (!CommonOptionsAreValid(*this, error)) {
+    return false;
+  }
+
+  if (minimizer_type == TRUST_REGION &&
+      !TrustRegionOptionsAreValid(*this, error)) {
+    return false;
+  }
+
+  // We do not know if the problem is bounds constrained or not, if it
+  // is then the trust region solver will also use the line search
+  // solver to do a projection onto the box constraints, so make sure
+  // that the line search options are checked independent of what
+  // minimizer algorithm is being used.
+  return LineSearchOptionsAreValid(*this, error);
+}
+
+Solver::~Solver() {}
+
+void Solver::Solve(const Solver::Options& options,
+                   Problem* problem,
+                   Solver::Summary* summary) {
+  using internal::PreprocessedProblem;
+  using internal::Preprocessor;
+  using internal::ProblemImpl;
+  using internal::Program;
+  using internal::WallTimeInSeconds;
+
+  CHECK(problem != nullptr);
+  CHECK(summary != nullptr);
+
+  double start_time = WallTimeInSeconds();
+  *summary = Summary();
+  if (!options.IsValid(&summary->message)) {
+    LOG(ERROR) << "Terminating: " << summary->message;
+    return;
+  }
+
+  ProblemImpl* problem_impl = problem->problem_impl_.get();
+  Program* program = problem_impl->mutable_program();
+  PreSolveSummarize(options, problem_impl, summary);
+
+  // If gradient_checking is enabled, wrap all cost functions in a
+  // gradient checker and install a callback that terminates if any gradient
+  // error is detected.
+  std::unique_ptr<internal::ProblemImpl> gradient_checking_problem;
+  internal::GradientCheckingIterationCallback gradient_checking_callback;
+  Solver::Options modified_options = options;
+  if (options.check_gradients) {
+    modified_options.callbacks.push_back(&gradient_checking_callback);
+    gradient_checking_problem.reset(
+        CreateGradientCheckingProblemImpl(
+            problem_impl,
+            options.gradient_check_numeric_derivative_relative_step_size,
+            options.gradient_check_relative_precision,
+            &gradient_checking_callback));
+    problem_impl = gradient_checking_problem.get();
+    program = problem_impl->mutable_program();
+  }
+
+  // Make sure that all the parameter blocks states are set to the
+  // values provided by the user.
+  program->SetParameterBlockStatePtrsToUserStatePtrs();
+
+  // The main thread also does work so we only need to launch num_threads - 1.
+  problem_impl->context()->EnsureMinimumThreads(options.num_threads - 1);
+
+  std::unique_ptr<Preprocessor> preprocessor(
+      Preprocessor::Create(modified_options.minimizer_type));
+  PreprocessedProblem pp;
+
+  const bool status = preprocessor->Preprocess(modified_options, problem_impl, &pp);
+
+  // We check the linear_solver_options.type rather than
+  // modified_options.linear_solver_type because, depending on the
+  // lack of a Schur structure, the preprocessor may change the linear
+  // solver type.
+  if (IsSchurType(pp.linear_solver_options.type)) {
+    // TODO(sameeragarwal): We can likely eliminate the duplicate call
+    // to DetectStructure here and inside the linear solver, by
+    // calling this in the preprocessor.
+    int row_block_size;
+    int e_block_size;
+    int f_block_size;
+    DetectStructure(*static_cast<internal::BlockSparseMatrix*>(
+                        pp.minimizer_options.jacobian.get())
+                    ->block_structure(),
+                    pp.linear_solver_options.elimination_groups[0],
+                    &row_block_size,
+                    &e_block_size,
+                    &f_block_size);
+    summary->schur_structure_given =
+        SchurStructureToString(row_block_size, e_block_size, f_block_size);
+    internal::GetBestSchurTemplateSpecialization(&row_block_size,
+                                                 &e_block_size,
+                                                 &f_block_size);
+    summary->schur_structure_used =
+        SchurStructureToString(row_block_size, e_block_size, f_block_size);
+  }
+
+  summary->fixed_cost = pp.fixed_cost;
+  summary->preprocessor_time_in_seconds = WallTimeInSeconds() - start_time;
+
+  if (status) {
+    const double minimizer_start_time = WallTimeInSeconds();
+    Minimize(&pp, summary);
+    summary->minimizer_time_in_seconds =
+        WallTimeInSeconds() - minimizer_start_time;
+  } else {
+    summary->message = pp.error;
+  }
+
+  const double postprocessor_start_time = WallTimeInSeconds();
+  problem_impl = problem->problem_impl_.get();
+  program = problem_impl->mutable_program();
+  // On exit, ensure that the parameter blocks again point at the user
+  // provided values and the parameter blocks are numbered according
+  // to their position in the original user provided program.
+  program->SetParameterBlockStatePtrsToUserStatePtrs();
+  program->SetParameterOffsetsAndIndex();
+  PostSolveSummarize(pp, summary);
+  summary->postprocessor_time_in_seconds =
+      WallTimeInSeconds() - postprocessor_start_time;
+
+  // If the gradient checker reported an error, we want to report FAILURE
+  // instead of USER_FAILURE and provide the error log.
+  if (gradient_checking_callback.gradient_error_detected()) {
+    summary->termination_type = FAILURE;
+    summary->message = gradient_checking_callback.error_log();
+  }
+
+  summary->total_time_in_seconds = WallTimeInSeconds() - start_time;
+}
+
+void Solve(const Solver::Options& options,
+           Problem* problem,
+           Solver::Summary* summary) {
+  Solver solver;
+  solver.Solve(options, problem, summary);
+}
+
+string Solver::Summary::BriefReport() const {
+  return StringPrintf("Ceres Solver Report: "
+                      "Iterations: %d, "
+                      "Initial cost: %e, "
+                      "Final cost: %e, "
+                      "Termination: %s",
+                      num_successful_steps + num_unsuccessful_steps,
+                      initial_cost,
+                      final_cost,
+                      TerminationTypeToString(termination_type));
+}
+
+string Solver::Summary::FullReport() const {
+  using internal::VersionString;
+
+  string report = string("\nSolver Summary (v " + VersionString() + ")\n\n");
+
+  StringAppendF(&report, "%45s    %21s\n", "Original", "Reduced");
+  StringAppendF(&report, "Parameter blocks    % 25d% 25d\n",
+                num_parameter_blocks, num_parameter_blocks_reduced);
+  StringAppendF(&report, "Parameters          % 25d% 25d\n",
+                num_parameters, num_parameters_reduced);
+  if (num_effective_parameters_reduced != num_parameters_reduced) {
+    StringAppendF(&report, "Effective parameters% 25d% 25d\n",
+                  num_effective_parameters, num_effective_parameters_reduced);
+  }
+  StringAppendF(&report, "Residual blocks     % 25d% 25d\n",
+                num_residual_blocks, num_residual_blocks_reduced);
+  StringAppendF(&report, "Residuals           % 25d% 25d\n",
+                num_residuals, num_residuals_reduced);
+
+  if (minimizer_type == TRUST_REGION) {
+    // TRUST_SEARCH HEADER
+    StringAppendF(&report, "\nMinimizer                 %19s\n",
+                  "TRUST_REGION");
+
+    if (linear_solver_type_used == DENSE_NORMAL_CHOLESKY ||
+        linear_solver_type_used == DENSE_SCHUR ||
+        linear_solver_type_used == DENSE_QR) {
+      StringAppendF(&report, "\nDense linear algebra library  %15s\n",
+                    DenseLinearAlgebraLibraryTypeToString(
+                        dense_linear_algebra_library_type));
+    }
+
+    if (linear_solver_type_used == SPARSE_NORMAL_CHOLESKY ||
+        linear_solver_type_used == SPARSE_SCHUR ||
+        (linear_solver_type_used == ITERATIVE_SCHUR &&
+         (preconditioner_type_used == CLUSTER_JACOBI ||
+          preconditioner_type_used == CLUSTER_TRIDIAGONAL))) {
+      StringAppendF(&report, "\nSparse linear algebra library %15s\n",
+                    SparseLinearAlgebraLibraryTypeToString(
+                        sparse_linear_algebra_library_type));
+    }
+
+    StringAppendF(&report, "Trust region strategy     %19s",
+                  TrustRegionStrategyTypeToString(
+                      trust_region_strategy_type));
+    if (trust_region_strategy_type == DOGLEG) {
+      if (dogleg_type == TRADITIONAL_DOGLEG) {
+        StringAppendF(&report, " (TRADITIONAL)");
+      } else {
+        StringAppendF(&report, " (SUBSPACE)");
+      }
+    }
+    StringAppendF(&report, "\n");
+    StringAppendF(&report, "\n");
+
+    StringAppendF(&report, "%45s    %21s\n", "Given",  "Used");
+    StringAppendF(&report, "Linear solver       %25s%25s\n",
+                  LinearSolverTypeToString(linear_solver_type_given),
+                  LinearSolverTypeToString(linear_solver_type_used));
+
+    if (linear_solver_type_given == CGNR ||
+        linear_solver_type_given == ITERATIVE_SCHUR) {
+      StringAppendF(&report, "Preconditioner      %25s%25s\n",
+                    PreconditionerTypeToString(preconditioner_type_given),
+                    PreconditionerTypeToString(preconditioner_type_used));
+    }
+
+    if (preconditioner_type_used == CLUSTER_JACOBI ||
+        preconditioner_type_used == CLUSTER_TRIDIAGONAL) {
+      StringAppendF(&report, "Visibility clustering%24s%25s\n",
+                    VisibilityClusteringTypeToString(
+                        visibility_clustering_type),
+                    VisibilityClusteringTypeToString(
+                        visibility_clustering_type));
+    }
+    StringAppendF(&report, "Threads             % 25d% 25d\n",
+                  num_threads_given, num_threads_used);
+
+    string given;
+    StringifyOrdering(linear_solver_ordering_given, &given);
+    string used;
+    StringifyOrdering(linear_solver_ordering_used, &used);
+    StringAppendF(&report,
+                  "Linear solver ordering %22s %24s\n",
+                  given.c_str(),
+                  used.c_str());
+    if (IsSchurType(linear_solver_type_used)) {
+      StringAppendF(&report,
+                    "Schur structure        %22s %24s\n",
+                    schur_structure_given.c_str(),
+                    schur_structure_used.c_str());
+    }
+
+    if (inner_iterations_given) {
+      StringAppendF(&report,
+                    "Use inner iterations     %20s     %20s\n",
+                    inner_iterations_given ? "True" : "False",
+                    inner_iterations_used ? "True" : "False");
+    }
+
+    if (inner_iterations_used) {
+      string given;
+      StringifyOrdering(inner_iteration_ordering_given, &given);
+      string used;
+      StringifyOrdering(inner_iteration_ordering_used, &used);
+    StringAppendF(&report,
+                  "Inner iteration ordering %20s %24s\n",
+                  given.c_str(),
+                  used.c_str());
+    }
+  } else {
+    // LINE_SEARCH HEADER
+    StringAppendF(&report, "\nMinimizer                 %19s\n", "LINE_SEARCH");
+
+
+    string line_search_direction_string;
+    if (line_search_direction_type == LBFGS) {
+      line_search_direction_string = StringPrintf("LBFGS (%d)", max_lbfgs_rank);
+    } else if (line_search_direction_type == NONLINEAR_CONJUGATE_GRADIENT) {
+      line_search_direction_string =
+          NonlinearConjugateGradientTypeToString(
+              nonlinear_conjugate_gradient_type);
+    } else {
+      line_search_direction_string =
+          LineSearchDirectionTypeToString(line_search_direction_type);
+    }
+
+    StringAppendF(&report, "Line search direction     %19s\n",
+                  line_search_direction_string.c_str());
+
+    const string line_search_type_string =
+        StringPrintf("%s %s",
+                     LineSearchInterpolationTypeToString(
+                         line_search_interpolation_type),
+                     LineSearchTypeToString(line_search_type));
+    StringAppendF(&report, "Line search type          %19s\n",
+                  line_search_type_string.c_str());
+    StringAppendF(&report, "\n");
+
+    StringAppendF(&report, "%45s    %21s\n", "Given",  "Used");
+    StringAppendF(&report, "Threads             % 25d% 25d\n",
+                  num_threads_given, num_threads_used);
+  }
+
+  StringAppendF(&report, "\nCost:\n");
+  StringAppendF(&report, "Initial        % 30e\n", initial_cost);
+  if (termination_type != FAILURE &&
+      termination_type != USER_FAILURE) {
+    StringAppendF(&report, "Final          % 30e\n", final_cost);
+    StringAppendF(&report, "Change         % 30e\n",
+                  initial_cost - final_cost);
+  }
+
+  StringAppendF(&report, "\nMinimizer iterations         % 16d\n",
+                num_successful_steps + num_unsuccessful_steps);
+
+  // Successful/Unsuccessful steps only matter in the case of the
+  // trust region solver. Line search terminates when it encounters
+  // the first unsuccessful step.
+  if (minimizer_type == TRUST_REGION) {
+    StringAppendF(&report, "Successful steps               % 14d\n",
+                  num_successful_steps);
+    StringAppendF(&report, "Unsuccessful steps             % 14d\n",
+                  num_unsuccessful_steps);
+  }
+  if (inner_iterations_used) {
+    StringAppendF(&report, "Steps with inner iterations    % 14d\n",
+                  num_inner_iteration_steps);
+  }
+
+  const bool line_search_used =
+      (minimizer_type == LINE_SEARCH ||
+       (minimizer_type == TRUST_REGION && is_constrained));
+
+  if (line_search_used) {
+    StringAppendF(&report, "Line search steps              % 14d\n",
+                  num_line_search_steps);
+  }
+
+  StringAppendF(&report, "\nTime (in seconds):\n");
+  StringAppendF(&report, "Preprocessor        %25.6f\n",
+                preprocessor_time_in_seconds);
+
+  StringAppendF(&report, "\n  Residual only evaluation %18.6f (%d)\n",
+                residual_evaluation_time_in_seconds, num_residual_evaluations);
+  if (line_search_used) {
+    StringAppendF(&report, "    Line search cost evaluation    %10.6f\n",
+                  line_search_cost_evaluation_time_in_seconds);
+  }
+  StringAppendF(&report, "  Jacobian & residual evaluation %12.6f (%d)\n",
+                jacobian_evaluation_time_in_seconds, num_jacobian_evaluations);
+  if (line_search_used) {
+    StringAppendF(&report, "    Line search gradient evaluation   %6.6f\n",
+                  line_search_gradient_evaluation_time_in_seconds);
+  }
+
+  if (minimizer_type == TRUST_REGION) {
+    StringAppendF(&report, "  Linear solver       %23.6f (%d)\n",
+                  linear_solver_time_in_seconds, num_linear_solves);
+  }
+
+  if (inner_iterations_used) {
+    StringAppendF(&report, "  Inner iterations    %23.6f\n",
+                  inner_iteration_time_in_seconds);
+  }
+
+  if (line_search_used) {
+    StringAppendF(&report, "  Line search polynomial minimization  %.6f\n",
+                  line_search_polynomial_minimization_time_in_seconds);
+  }
+
+  StringAppendF(&report, "Minimizer           %25.6f\n\n",
+                minimizer_time_in_seconds);
+
+  StringAppendF(&report, "Postprocessor        %24.6f\n",
+                postprocessor_time_in_seconds);
+
+  StringAppendF(&report, "Total               %25.6f\n\n",
+                total_time_in_seconds);
+
+  StringAppendF(&report, "Termination:        %25s (%s)\n",
+                TerminationTypeToString(termination_type), message.c_str());
+  return report;
+}
+
+bool Solver::Summary::IsSolutionUsable() const {
+  return internal::IsSolutionUsable(*this);
+}
+
+}  // namespace ceres