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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 #ifndef CERES_INTERNAL_BLOCK_RANDOM_ACCESS_SPARSE_MATRIX_H_
     32 #define CERES_INTERNAL_BLOCK_RANDOM_ACCESS_SPARSE_MATRIX_H_
     33 
     34 #include <set>
     35 #include <vector>
     36 #include <utility>
     37 #include "ceres/mutex.h"
     38 #include "ceres/block_random_access_matrix.h"
     39 #include "ceres/collections_port.h"
     40 #include "ceres/triplet_sparse_matrix.h"
     41 #include "ceres/integral_types.h"
     42 #include "ceres/internal/macros.h"
     43 #include "ceres/internal/port.h"
     44 #include "ceres/internal/scoped_ptr.h"
     45 #include "ceres/types.h"
     46 
     47 namespace ceres {
     48 namespace internal {
     49 
     50 // A thread safe square block sparse implementation of
     51 // BlockRandomAccessMatrix. Internally a TripletSparseMatrix is used
     52 // for doing the actual storage. This class augments this matrix with
     53 // an unordered_map that allows random read/write access.
     54 class BlockRandomAccessSparseMatrix : public BlockRandomAccessMatrix {
     55  public:
     56   // blocks is an array of block sizes. block_pairs is a set of
     57   // <row_block_id, col_block_id> pairs to identify the non-zero cells
     58   // of this matrix.
     59   BlockRandomAccessSparseMatrix(const vector<int>& blocks,
     60                                 const set<pair<int, int> >& block_pairs);
     61 
     62   // The destructor is not thread safe. It assumes that no one is
     63   // modifying any cells when the matrix is being destroyed.
     64   virtual ~BlockRandomAccessSparseMatrix();
     65 
     66   // BlockRandomAccessMatrix Interface.
     67   virtual CellInfo* GetCell(int row_block_id,
     68                             int col_block_id,
     69                             int* row,
     70                             int* col,
     71                             int* row_stride,
     72                             int* col_stride);
     73 
     74   // This is not a thread safe method, it assumes that no cell is
     75   // locked.
     76   virtual void SetZero();
     77 
     78   // Since the matrix is square, num_rows() == num_cols().
     79   virtual int num_rows() const { return tsm_->num_rows(); }
     80   virtual int num_cols() const { return tsm_->num_cols(); }
     81 
     82   // Access to the underlying matrix object.
     83   const TripletSparseMatrix* matrix() const { return tsm_.get(); }
     84   TripletSparseMatrix* mutable_matrix() { return tsm_.get(); }
     85 
     86  private:
     87   int64 IntPairToLong(int a, int b) {
     88     return a * kMaxRowBlocks + b;
     89   }
     90 
     91   const int64 kMaxRowBlocks;
     92   // row/column block sizes.
     93   const vector<int> blocks_;
     94 
     95   // A mapping from <row_block_id, col_block_id> to the position in
     96   // the values array of tsm_ where the block is stored.
     97   typedef HashMap<long int, CellInfo* > LayoutType;
     98   LayoutType layout_;
     99 
    100   // The underlying matrix object which actually stores the cells.
    101   scoped_ptr<TripletSparseMatrix> tsm_;
    102 
    103   friend class BlockRandomAccessSparseMatrixTest;
    104   CERES_DISALLOW_COPY_AND_ASSIGN(BlockRandomAccessSparseMatrix);
    105 };
    106 
    107 }  // namespace internal
    108 }  // namespace ceres
    109 
    110 #endif  // CERES_INTERNAL_BLOCK_RANDOM_ACCESS_SPARSE_MATRIX_H_
    111