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      1 // Ceres Solver - A fast non-linear least squares minimizer
      2 // Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
      3 // http://code.google.com/p/ceres-solver/
      4 //
      5 // Redistribution and use in source and binary forms, with or without
      6 // modification, are permitted provided that the following conditions are met:
      7 //
      8 // * Redistributions of source code must retain the above copyright notice,
      9 //   this list of conditions and the following disclaimer.
     10 // * Redistributions in binary form must reproduce the above copyright notice,
     11 //   this list of conditions and the following disclaimer in the documentation
     12 //   and/or other materials provided with the distribution.
     13 // * Neither the name of Google Inc. nor the names of its contributors may be
     14 //   used to endorse or promote products derived from this software without
     15 //   specific prior written permission.
     16 //
     17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
     18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
     21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     27 // POSSIBILITY OF SUCH DAMAGE.
     28 //
     29 // Author: sameeragarwal (at) google.com (Sameer Agarwal)
     30 
     31 #include "ceres/sparse_normal_cholesky_solver.h"
     32 
     33 #include <algorithm>
     34 #include <cstring>
     35 #include <ctime>
     36 
     37 #ifndef CERES_NO_CXSPARSE
     38 #include "cs.h"
     39 #endif
     40 
     41 #include "ceres/compressed_row_sparse_matrix.h"
     42 #include "ceres/linear_solver.h"
     43 #include "ceres/suitesparse.h"
     44 #include "ceres/triplet_sparse_matrix.h"
     45 #include "ceres/internal/eigen.h"
     46 #include "ceres/internal/scoped_ptr.h"
     47 #include "ceres/types.h"
     48 
     49 namespace ceres {
     50 namespace internal {
     51 
     52 SparseNormalCholeskySolver::SparseNormalCholeskySolver(
     53     const LinearSolver::Options& options)
     54     : options_(options) {
     55 #ifndef CERES_NO_SUITESPARSE
     56   factor_ = NULL;
     57 #endif
     58 
     59 #ifndef CERES_NO_CXSPARSE
     60   cxsparse_factor_ = NULL;
     61 #endif  // CERES_NO_CXSPARSE
     62 }
     63 
     64 SparseNormalCholeskySolver::~SparseNormalCholeskySolver() {
     65 #ifndef CERES_NO_SUITESPARSE
     66   if (factor_ != NULL) {
     67     ss_.Free(factor_);
     68     factor_ = NULL;
     69   }
     70 #endif
     71 
     72 #ifndef CERES_NO_CXSPARSE
     73   if (cxsparse_factor_ != NULL) {
     74     cxsparse_.Free(cxsparse_factor_);
     75     cxsparse_factor_ = NULL;
     76   }
     77 #endif  // CERES_NO_CXSPARSE
     78 }
     79 
     80 LinearSolver::Summary SparseNormalCholeskySolver::SolveImpl(
     81     CompressedRowSparseMatrix* A,
     82     const double* b,
     83     const LinearSolver::PerSolveOptions& per_solve_options,
     84     double * x) {
     85   switch (options_.sparse_linear_algebra_library) {
     86     case SUITE_SPARSE:
     87       return SolveImplUsingSuiteSparse(A, b, per_solve_options, x);
     88     case CX_SPARSE:
     89       return SolveImplUsingCXSparse(A, b, per_solve_options, x);
     90     default:
     91       LOG(FATAL) << "Unknown sparse linear algebra library : "
     92                  << options_.sparse_linear_algebra_library;
     93   }
     94 
     95   LOG(FATAL) << "Unknown sparse linear algebra library : "
     96              << options_.sparse_linear_algebra_library;
     97   return LinearSolver::Summary();
     98 }
     99 
    100 #ifndef CERES_NO_CXSPARSE
    101 LinearSolver::Summary SparseNormalCholeskySolver::SolveImplUsingCXSparse(
    102     CompressedRowSparseMatrix* A,
    103     const double* b,
    104     const LinearSolver::PerSolveOptions& per_solve_options,
    105     double * x) {
    106   LinearSolver::Summary summary;
    107   summary.num_iterations = 1;
    108   const int num_cols = A->num_cols();
    109   Vector Atb = Vector::Zero(num_cols);
    110   A->LeftMultiply(b, Atb.data());
    111 
    112   if (per_solve_options.D != NULL) {
    113     // Temporarily append a diagonal block to the A matrix, but undo
    114     // it before returning the matrix to the user.
    115     CompressedRowSparseMatrix D(per_solve_options.D, num_cols);
    116     A->AppendRows(D);
    117   }
    118 
    119   VectorRef(x, num_cols).setZero();
    120 
    121   // Wrap the augmented Jacobian in a compressed sparse column matrix.
    122   cs_di At = cxsparse_.CreateSparseMatrixTransposeView(A);
    123 
    124   // Compute the normal equations. J'J delta = J'f and solve them
    125   // using a sparse Cholesky factorization. Notice that when compared
    126   // to SuiteSparse we have to explicitly compute the transpose of Jt,
    127   // and then the normal equations before they can be
    128   // factorized. CHOLMOD/SuiteSparse on the other hand can just work
    129   // off of Jt to compute the Cholesky factorization of the normal
    130   // equations.
    131   cs_di* A2 = cs_transpose(&At, 1);
    132   cs_di* AtA = cs_multiply(&At,A2);
    133 
    134   cxsparse_.Free(A2);
    135   if (per_solve_options.D != NULL) {
    136     A->DeleteRows(num_cols);
    137   }
    138 
    139   // Compute symbolic factorization if not available.
    140   if (cxsparse_factor_ == NULL) {
    141     cxsparse_factor_ = CHECK_NOTNULL(cxsparse_.AnalyzeCholesky(AtA));
    142   }
    143 
    144   // Solve the linear system.
    145   if (cxsparse_.SolveCholesky(AtA, cxsparse_factor_, Atb.data())) {
    146     VectorRef(x, Atb.rows()) = Atb;
    147     summary.termination_type = TOLERANCE;
    148   }
    149 
    150   cxsparse_.Free(AtA);
    151   return summary;
    152 }
    153 #else
    154 LinearSolver::Summary SparseNormalCholeskySolver::SolveImplUsingCXSparse(
    155     CompressedRowSparseMatrix* A,
    156     const double* b,
    157     const LinearSolver::PerSolveOptions& per_solve_options,
    158     double * x) {
    159   LOG(FATAL) << "No CXSparse support in Ceres.";
    160 
    161   // Unreachable but MSVC does not know this.
    162   return LinearSolver::Summary();
    163 }
    164 #endif
    165 
    166 #ifndef CERES_NO_SUITESPARSE
    167 LinearSolver::Summary SparseNormalCholeskySolver::SolveImplUsingSuiteSparse(
    168     CompressedRowSparseMatrix* A,
    169     const double* b,
    170     const LinearSolver::PerSolveOptions& per_solve_options,
    171     double * x) {
    172   const time_t start_time = time(NULL);
    173   const int num_cols = A->num_cols();
    174 
    175   LinearSolver::Summary summary;
    176   Vector Atb = Vector::Zero(num_cols);
    177   A->LeftMultiply(b, Atb.data());
    178 
    179   if (per_solve_options.D != NULL) {
    180     // Temporarily append a diagonal block to the A matrix, but undo it before
    181     // returning the matrix to the user.
    182     CompressedRowSparseMatrix D(per_solve_options.D, num_cols);
    183     A->AppendRows(D);
    184   }
    185 
    186   VectorRef(x, num_cols).setZero();
    187 
    188   scoped_ptr<cholmod_sparse> lhs(ss_.CreateSparseMatrixTransposeView(A));
    189   CHECK_NOTNULL(lhs.get());
    190 
    191   cholmod_dense* rhs = ss_.CreateDenseVector(Atb.data(), num_cols, num_cols);
    192   const time_t init_time = time(NULL);
    193 
    194   if (factor_ == NULL) {
    195     if (options_.use_block_amd) {
    196       factor_ = ss_.BlockAnalyzeCholesky(lhs.get(),
    197                                          A->col_blocks(),
    198                                          A->row_blocks());
    199     } else {
    200       factor_ = ss_.AnalyzeCholesky(lhs.get());
    201     }
    202 
    203     if (VLOG_IS_ON(2)) {
    204       cholmod_print_common("Symbolic Analysis", ss_.mutable_cc());
    205     }
    206   }
    207 
    208   CHECK_NOTNULL(factor_);
    209 
    210   const time_t symbolic_time = time(NULL);
    211 
    212   cholmod_dense* sol = ss_.SolveCholesky(lhs.get(), factor_, rhs);
    213   const time_t solve_time = time(NULL);
    214 
    215   ss_.Free(rhs);
    216   rhs = NULL;
    217 
    218   if (per_solve_options.D != NULL) {
    219     A->DeleteRows(num_cols);
    220   }
    221 
    222   summary.num_iterations = 1;
    223   if (sol != NULL) {
    224     memcpy(x, sol->x, num_cols * sizeof(*x));
    225 
    226     ss_.Free(sol);
    227     sol = NULL;
    228     summary.termination_type = TOLERANCE;
    229   }
    230 
    231   const time_t cleanup_time = time(NULL);
    232   VLOG(2) << "time (sec) total: " << (cleanup_time - start_time)
    233           << " init: " << (init_time - start_time)
    234           << " symbolic: " << (symbolic_time - init_time)
    235           << " solve: " << (solve_time - symbolic_time)
    236           << " cleanup: " << (cleanup_time - solve_time);
    237   return summary;
    238 }
    239 #else
    240 LinearSolver::Summary SparseNormalCholeskySolver::SolveImplUsingSuiteSparse(
    241     CompressedRowSparseMatrix* A,
    242     const double* b,
    243     const LinearSolver::PerSolveOptions& per_solve_options,
    244     double * x) {
    245   LOG(FATAL) << "No SuiteSparse support in Ceres.";
    246 
    247   // Unreachable but MSVC does not know this.
    248   return LinearSolver::Summary();
    249 }
    250 #endif
    251 
    252 }   // namespace internal
    253 }   // namespace ceres
    254