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Diffstat (limited to 'internal/ceres/block_random_access_matrix.h')
| -rw-r--r-- | internal/ceres/block_random_access_matrix.h | 132 |
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diff --git a/internal/ceres/block_random_access_matrix.h b/internal/ceres/block_random_access_matrix.h new file mode 100644 index 0000000..b76cb78 --- /dev/null +++ b/internal/ceres/block_random_access_matrix.h @@ -0,0 +1,132 @@ +// Ceres Solver - A fast non-linear least squares minimizer +// Copyright 2010, 2011, 2012 Google Inc. All rights reserved. +// http://code.google.com/p/ceres-solver/ +// +// 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: sameeragarwal@google.com (Sameer Agarwal) +// +// Interface for matrices that allow block based random access. + +#ifndef CERES_INTERNAL_BLOCK_RANDOM_ACCESS_MATRIX_H_ +#define CERES_INTERNAL_BLOCK_RANDOM_ACCESS_MATRIX_H_ + +#include "ceres/mutex.h" + +namespace ceres { +namespace internal { + +// A matrix implementing the BlockRandomAccessMatrix interface is a +// matrix whose rows and columns are divided into blocks. For example +// the matrix A: +// +// 3 4 5 +// A = 5 [c_11 c_12 c_13] +// 4 [c_21 c_22 c_23] +// +// has row blocks of size 5 and 4, and column blocks of size 3, 4 and +// 5. It has six cells corresponding to the six row-column block +// combinations. +// +// BlockRandomAccessMatrix objects provide access to cells c_ij using +// the GetCell method. when a cell is present, GetCell will return a +// CellInfo object containing a pointer to an array which contains the +// cell as a submatrix and a mutex that guards this submatrix. If the +// user is accessing the matrix concurrently, it is his responsibility +// to use the mutex to exclude other writers from writing to the cell +// concurrently. +// +// There is no requirement that all cells be present, i.e. the matrix +// itself can be block sparse. When a cell is not present, the GetCell +// method will return a NULL pointer. +// +// There is no requirement about how the cells are stored beyond that +// form a dense submatrix of a larger dense matrix. Like everywhere +// else in Ceres, RowMajor storage assumed. +// +// Example usage: +// +// BlockRandomAccessMatrix* A = new BlockRandomAccessMatrixSubClass(...) +// +// int row, col, row_stride, col_stride; +// CellInfo* cell = A->GetCell(row_block_id, col_block_id, +// &row, &col, +// &row_stride, &col_stride); +// +// if (cell != NULL) { +// MatrixRef m(cell->values, row_stride, col_stride); +// CeresMutexLock l(&cell->m); +// m.block(row, col, row_block_size, col_block_size) = ... +// } + +// Structure to carry a pointer to the array containing a cell and the +// Mutex guarding it. +struct CellInfo { + CellInfo() + : values(NULL) { + } + + explicit CellInfo(double* ptr) + : values(ptr) { + } + + double* values; + Mutex m; +}; + +class BlockRandomAccessMatrix { + public: + virtual ~BlockRandomAccessMatrix(); + + // If the cell (row_block_id, col_block_id) is present, then return + // a CellInfo with a pointer to the dense matrix containing it, + // otherwise return NULL. The dense matrix containing this cell has + // size row_stride, col_stride and the cell is located at position + // (row, col) within this matrix. + // + // The size of the cell is row_block_size x col_block_size is + // assumed known to the caller. row_block_size less than or equal to + // row_stride and col_block_size is upper bounded by col_stride. + virtual CellInfo* GetCell(int row_block_id, + int col_block_id, + int* row, + int* col, + int* row_stride, + int* col_stride) = 0; + + // Zero out the values of the array. The structure of the matrix + // (size and sparsity) is preserved. + virtual void SetZero() = 0; + + // Number of scalar rows and columns in the matrix, i.e the sum of + // all row blocks and column block sizes respectively. + virtual int num_rows() const = 0; + virtual int num_cols() const = 0; +}; + +} // namespace internal +} // namespace ceres + +#endif // CERES_INTERNAL_BLOCK_RANDOM_ACCESS_MATRIX_H_ |