| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2015 Google Inc. All rights reserved. |
| // http://ceres-solver.org/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
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| // 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. |
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| // specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| // |
| // Author: sameeragarwal@google.com (Sameer Agarwal) |
| // |
| // Interface definition for sparse matrices. |
| |
| #ifndef CERES_INTERNAL_SPARSE_MATRIX_H_ |
| #define CERES_INTERNAL_SPARSE_MATRIX_H_ |
| |
| #include <cstdio> |
| #include "ceres/linear_operator.h" |
| #include "ceres/internal/eigen.h" |
| #include "ceres/types.h" |
| |
| namespace ceres { |
| namespace internal { |
| |
| // This class defines the interface for storing and manipulating |
| // sparse matrices. The key property that differentiates different |
| // sparse matrices is how they are organized in memory and how the |
| // information about the sparsity structure of the matrix is |
| // stored. This has significant implications for linear solvers |
| // operating on these matrices. |
| // |
| // To deal with the different kinds of layouts, we will assume that a |
| // sparse matrix will have a two part representation. A values array |
| // that will be used to store the entries of the sparse matrix and |
| // some sort of a layout object that tells the user the sparsity |
| // structure and layout of the values array. For example in case of |
| // the TripletSparseMatrix, this information is carried in the rows |
| // and cols arrays and for the BlockSparseMatrix, this information is |
| // carried in the CompressedRowBlockStructure object. |
| // |
| // This interface deliberately does not contain any information about |
| // the structure of the sparse matrix as that seems to be highly |
| // matrix type dependent and we are at this stage unable to come up |
| // with an efficient high level interface that spans multiple sparse |
| // matrix types. |
| class SparseMatrix : public LinearOperator { |
| public: |
| virtual ~SparseMatrix(); |
| |
| // y += Ax; |
| virtual void RightMultiply(const double* x, double* y) const = 0; |
| // y += A'x; |
| virtual void LeftMultiply(const double* x, double* y) const = 0; |
| |
| // In MATLAB notation sum(A.*A, 1) |
| virtual void SquaredColumnNorm(double* x) const = 0; |
| // A = A * diag(scale) |
| virtual void ScaleColumns(const double* scale) = 0; |
| |
| // A = 0. A->num_nonzeros() == 0 is true after this call. The |
| // sparsity pattern is preserved. |
| virtual void SetZero() = 0; |
| |
| // Resize and populate dense_matrix with a dense version of the |
| // sparse matrix. |
| virtual void ToDenseMatrix(Matrix* dense_matrix) const = 0; |
| |
| // Write out the matrix as a sequence of (i,j,s) triplets. This |
| // format is useful for loading the matrix into MATLAB/octave as a |
| // sparse matrix. |
| virtual void ToTextFile(FILE* file) const = 0; |
| |
| // Accessors for the values array that stores the entries of the |
| // sparse matrix. The exact interpreptation of the values of this |
| // array depends on the particular kind of SparseMatrix being |
| // accessed. |
| virtual double* mutable_values() = 0; |
| virtual const double* values() const = 0; |
| |
| virtual int num_rows() const = 0; |
| virtual int num_cols() const = 0; |
| virtual int num_nonzeros() const = 0; |
| }; |
| |
| } // namespace internal |
| } // namespace ceres |
| |
| #endif // CERES_INTERNAL_SPARSE_MATRIX_H_ |