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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
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     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 // For generalized bi-partite Jacobian matrices that arise in
     32 // Structure from Motion related problems, it is sometimes useful to
     33 // have access to the two parts of the matrix as linear operators
     34 // themselves. This class provides that functionality.
     35 
     36 #ifndef CERES_INTERNAL_PARTITIONED_MATRIX_VIEW_H_
     37 #define CERES_INTERNAL_PARTITIONED_MATRIX_VIEW_H_
     38 
     39 #include "ceres/block_sparse_matrix.h"
     40 
     41 namespace ceres {
     42 namespace internal {
     43 
     44 // Given generalized bi-partite matrix A = [E F], with the same block
     45 // structure as required by the Schur complement based solver, found
     46 // in explicit_schur_complement_solver.h, provide access to the
     47 // matrices E and F and their outer products E'E and F'F with
     48 // themselves.
     49 //
     50 // Lack of BlockStructure object will result in a crash and if the
     51 // block structure of the matrix does not satisfy the requirements of
     52 // the Schur complement solver it will result in unpredictable and
     53 // wrong output.
     54 //
     55 // This class lives in the internal name space as its a utility class
     56 // to be used by the IterativeSchurComplementSolver class, found in
     57 // iterative_schur_complement_solver.h, and is not meant for general
     58 // consumption.
     59 class PartitionedMatrixView {
     60  public:
     61   // matrix = [E F], where the matrix E contains the first
     62   // num_col_blocks_a column blocks.
     63   PartitionedMatrixView(const BlockSparseMatrix& matrix,
     64                         int num_col_blocks_a);
     65   ~PartitionedMatrixView();
     66 
     67   // y += E'x
     68   void LeftMultiplyE(const double* x, double* y) const;
     69 
     70   // y += F'x
     71   void LeftMultiplyF(const double* x, double* y) const;
     72 
     73   // y += Ex
     74   void RightMultiplyE(const double* x, double* y) const;
     75 
     76   // y += Fx
     77   void RightMultiplyF(const double* x, double* y) const;
     78 
     79   // Create and return the block diagonal of the matrix E'E.
     80   BlockSparseMatrix* CreateBlockDiagonalEtE() const;
     81 
     82   // Create and return the block diagonal of the matrix F'F.
     83   BlockSparseMatrix* CreateBlockDiagonalFtF() const;
     84 
     85   // Compute the block diagonal of the matrix E'E and store it in
     86   // block_diagonal. The matrix block_diagonal is expected to have a
     87   // BlockStructure (preferably created using
     88   // CreateBlockDiagonalMatrixEtE) which is has the same structure as
     89   // the block diagonal of E'E.
     90   void UpdateBlockDiagonalEtE(BlockSparseMatrix* block_diagonal) const;
     91 
     92   // Compute the block diagonal of the matrix F'F and store it in
     93   // block_diagonal. The matrix block_diagonal is expected to have a
     94   // BlockStructure (preferably created using
     95   // CreateBlockDiagonalMatrixFtF) which is has the same structure as
     96   // the block diagonal of F'F.
     97   void UpdateBlockDiagonalFtF(BlockSparseMatrix* block_diagonal) const;
     98 
     99   int num_col_blocks_e() const { return num_col_blocks_e_;  }
    100   int num_col_blocks_f() const { return num_col_blocks_f_;  }
    101   int num_cols_e()       const { return num_cols_e_;        }
    102   int num_cols_f()       const { return num_cols_f_;        }
    103   int num_rows()         const { return matrix_.num_rows(); }
    104   int num_cols()         const { return matrix_.num_cols(); }
    105 
    106  private:
    107   BlockSparseMatrix* CreateBlockDiagonalMatrixLayout(int start_col_block,
    108                                                      int end_col_block) const;
    109 
    110   const BlockSparseMatrix& matrix_;
    111   int num_row_blocks_e_;
    112   int num_col_blocks_e_;
    113   int num_col_blocks_f_;
    114   int num_cols_e_;
    115   int num_cols_f_;
    116 };
    117 
    118 }  // namespace internal
    119 }  // namespace ceres
    120 
    121 #endif  // CERES_INTERNAL_PARTITIONED_MATRIX_VIEW_H_
    122