[35] | 1 | /*! |
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| 2 | * \file |
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| 3 | * \brief Definitions of Cholesky factorisation functions |
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| 4 | * \author Tony Ottosson |
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| 5 | * |
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| 6 | * ------------------------------------------------------------------------- |
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| 7 | * |
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| 8 | * IT++ - C++ library of mathematical, signal processing, speech processing, |
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| 9 | * and communications classes and functions |
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| 10 | * |
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| 11 | * Copyright (C) 1995-2007 (see AUTHORS file for a list of contributors) |
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| 12 | * |
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| 13 | * This program is free software; you can redistribute it and/or modify |
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| 14 | * it under the terms of the GNU General Public License as published by |
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| 15 | * the Free Software Foundation; either version 2 of the License, or |
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| 16 | * (at your option) any later version. |
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| 17 | * |
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| 18 | * This program is distributed in the hope that it will be useful, |
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| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 21 | * GNU General Public License for more details. |
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| 22 | * |
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| 23 | * You should have received a copy of the GNU General Public License |
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| 24 | * along with this program; if not, write to the Free Software |
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| 25 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 26 | * |
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| 27 | * ------------------------------------------------------------------------- |
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| 28 | */ |
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| 29 | |
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| 30 | #ifndef CHOLESKY_H |
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| 31 | #define CHOLESKY_H |
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| 32 | |
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| 33 | #include <itpp/base/mat.h> |
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| 34 | |
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| 35 | |
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| 36 | namespace itpp { |
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| 37 | |
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| 38 | /*! \addtogroup matrixdecomp |
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| 39 | */ |
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| 40 | //!@{ |
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| 41 | |
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| 42 | /*! |
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| 43 | \brief Cholesky factorisation of real symmetric and positive definite matrix |
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| 44 | |
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| 45 | The Cholesky factorisation of a real symmetric positive-definite matrix \f$\mathbf{X}\f$ |
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| 46 | of size \f$n \times n\f$ is given by |
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| 47 | \f[ |
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| 48 | \mathbf{X} = \mathbf{F}^T \mathbf{F} |
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| 49 | \f] |
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| 50 | where \f$\mathbf{F}\f$ is an upper trangular \f$n \times n\f$ matrix. |
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| 51 | |
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| 52 | Returns true if calcuation succeeded. False otherwise. |
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| 53 | */ |
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| 54 | bool chol(const mat &X, mat &F); |
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| 55 | |
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| 56 | /*! |
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| 57 | \brief Cholesky factorisation of real symmetric and positive definite matrix |
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| 58 | |
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| 59 | The Cholesky factorisation of a real symmetric positive-definite matrix \f$\mathbf{X}\f$ |
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| 60 | of size \f$n \times n\f$ is given by |
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| 61 | \f[ |
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| 62 | \mathbf{X} = \mathbf{F}^T \mathbf{F} |
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| 63 | \f] |
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| 64 | where \f$\mathbf{F}\f$ is an upper trangular \f$n \times n\f$ matrix. |
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| 65 | */ |
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| 66 | mat chol(const mat &X); |
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| 67 | |
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| 68 | |
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| 69 | /*! |
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| 70 | \brief Cholesky factorisation of complex hermitian and positive-definite matrix |
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| 71 | |
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| 72 | The Cholesky factorisation of a hermitian positive-definite matrix \f$\mathbf{X}\f$ |
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| 73 | of size \f$n \times n\f$ is given by |
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| 74 | \f[ |
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| 75 | \mathbf{X} = \mathbf{F}^H \mathbf{F} |
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| 76 | \f] |
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| 77 | where \f$\mathbf{F}\f$ is an upper trangular \f$n \times n\f$ matrix. |
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| 78 | |
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| 79 | Returns true if calcuation succeeded. False otherwise. |
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| 80 | |
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| 81 | If \c X is positive definite, true is returned and \c F=chol(X) |
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| 82 | produces an upper triangular \c F. If also \c X is symmetric then \c F'*F = X. |
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| 83 | If \c X is not positive definite, false is returned. |
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| 84 | */ |
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| 85 | bool chol(const cmat &X, cmat &F); |
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| 86 | |
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| 87 | /*! |
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| 88 | \brief Cholesky factorisation of complex hermitian and positive-definite matrix |
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| 89 | |
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| 90 | The Cholesky factorisation of a hermitian positive-definite matrix \f$\mathbf{X}\f$ |
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| 91 | of size \f$n \times n\f$ is given by |
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| 92 | \f[ |
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| 93 | \mathbf{X} = \mathbf{F}^H \mathbf{F} |
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| 94 | \f] |
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| 95 | where \f$\mathbf{F}\f$ is an upper trangular \f$n \times n\f$ matrix. |
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| 96 | */ |
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| 97 | cmat chol(const cmat &X); |
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| 98 | |
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| 99 | //!@} |
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| 100 | |
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| 101 | } // namespace itpp |
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| 102 | |
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| 103 | #endif // #ifndef CHOLESKY_H |
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