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@google.com (Sameer Agarwal) 30 31 #ifndef CERES_INTERNAL_PARAMETER_BLOCK_ORDERING_H_ 32 #define CERES_INTERNAL_PARAMETER_BLOCK_ORDERING_H_ 33 34 #include <vector> 35 #include "ceres/ordered_groups.h" 36 #include "ceres/graph.h" 37 #include "ceres/types.h" 38 39 namespace ceres { 40 namespace internal { 41 42 class Program; 43 class ParameterBlock; 44 45 // Uses an approximate independent set ordering to order the parameter 46 // blocks of a problem so that it is suitable for use with Schur 47 // complement based solvers. The output variable ordering contains an 48 // ordering of the parameter blocks and the return value is size of 49 // the independent set or the number of e_blocks (see 50 // schur_complement_solver.h for an explanation). Constant parameters 51 // are added to the end. 52 // 53 // The ordering vector has the structure 54 // 55 // ordering = [independent set, 56 // complement of the independent set, 57 // fixed blocks] 58 int ComputeSchurOrdering(const Program& program, 59 vector<ParameterBlock* >* ordering); 60 61 // Same as above, except that ties while computing the independent set 62 // ordering are resolved in favour of the order in which the parameter 63 // blocks occur in the program. 64 int ComputeStableSchurOrdering(const Program& program, 65 vector<ParameterBlock* >* ordering); 66 67 // Use an approximate independent set ordering to decompose the 68 // parameter blocks of a problem in a sequence of independent 69 // sets. The ordering covers all the non-constant parameter blocks in 70 // the program. 71 void ComputeRecursiveIndependentSetOrdering(const Program& program, 72 ParameterBlockOrdering* ordering); 73 74 // Builds a graph on the parameter blocks of a Problem, whose 75 // structure reflects the sparsity structure of the Hessian. Each 76 // vertex corresponds to a parameter block in the Problem except for 77 // parameter blocks that are marked constant. An edge connects two 78 // parameter blocks, if they co-occur in a residual block. 79 Graph<ParameterBlock*>* CreateHessianGraph(const Program& program); 80 81 // Iterate over each of the groups in order of their priority and fill 82 // summary with their sizes. 83 void OrderingToGroupSizes(const ParameterBlockOrdering* ordering, 84 vector<int>* group_sizes); 85 86 } // namespace internal 87 } // namespace ceres 88 89 #endif // CERES_INTERNAL_PARAMETER_BLOCK_ORDERING_H_ 90