| 1 | /* | 
| 2 | * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved. | 
| 3 | * | 
| 4 | * The University of Notre Dame grants you ("Licensee") a | 
| 5 | * non-exclusive, royalty free, license to use, modify and | 
| 6 | * redistribute this software in source and binary code form, provided | 
| 7 | * that the following conditions are met: | 
| 8 | * | 
| 9 | * 1. Acknowledgement of the program authors must be made in any | 
| 10 | *    publication of scientific results based in part on use of the | 
| 11 | *    program.  An acceptable form of acknowledgement is citation of | 
| 12 | *    the article in which the program was described (Matthew | 
| 13 | *    A. Meineke, Charles F. Vardeman II, Teng Lin, Christopher | 
| 14 | *    J. Fennell and J. Daniel Gezelter, "OOPSE: An Object-Oriented | 
| 15 | *    Parallel Simulation Engine for Molecular Dynamics," | 
| 16 | *    J. Comput. Chem. 26, pp. 252-271 (2005)) | 
| 17 | * | 
| 18 | * 2. Redistributions of source code must retain the above copyright | 
| 19 | *    notice, this list of conditions and the following disclaimer. | 
| 20 | * | 
| 21 | * 3. Redistributions in binary form must reproduce the above copyright | 
| 22 | *    notice, this list of conditions and the following disclaimer in the | 
| 23 | *    documentation and/or other materials provided with the | 
| 24 | *    distribution. | 
| 25 | * | 
| 26 | * This software is provided "AS IS," without a warranty of any | 
| 27 | * kind. All express or implied conditions, representations and | 
| 28 | * warranties, including any implied warranty of merchantability, | 
| 29 | * fitness for a particular purpose or non-infringement, are hereby | 
| 30 | * excluded.  The University of Notre Dame and its licensors shall not | 
| 31 | * be liable for any damages suffered by licensee as a result of | 
| 32 | * using, modifying or distributing the software or its | 
| 33 | * derivatives. In no event will the University of Notre Dame or its | 
| 34 | * licensors be liable for any lost revenue, profit or data, or for | 
| 35 | * direct, indirect, special, consequential, incidental or punitive | 
| 36 | * damages, however caused and regardless of the theory of liability, | 
| 37 | * arising out of the use of or inability to use software, even if the | 
| 38 | * University of Notre Dame has been advised of the possibility of | 
| 39 | * such damages. | 
| 40 | */ | 
| 41 | #ifndef MATH_CHOLESKYDECOMPOSITION_HPP | 
| 42 | #define MATH_CHOLESKYDECOMPOSITION_HPP | 
| 43 |  | 
| 44 | namespace oopse { | 
| 45 | template<class MatrixType> | 
| 46 | int CholeskyDecomposition(MatrixType& A, MatrixType& L) { | 
| 47 | int n = A.getNRow(); | 
| 48 | assert(n == A.getNCol() && n == L.getNRow()&& n==L.getNCol()); | 
| 49 | for(int i = 0; i < n; ++i) { | 
| 50 | double sum1 = 0; | 
| 51 | for (int k = 0; k < i -1; ++k) { | 
| 52 | sum1 +=L(i,k)*L(i,k); | 
| 53 | } | 
| 54 | L(i, i) = sqrt(A(i, i) - sum1); | 
| 55 | for (int j = i+1; j < n; ++j) { | 
| 56 | double sum2 = 0; | 
| 57 | for (int k = 0; k < i-1; ++k) { | 
| 58 | sum2 += L(j ,k)*L(i, k); | 
| 59 | } | 
| 60 | A(j, i) = (A(j, i) - sum2) /L(i,i); | 
| 61 | } | 
| 62 | } | 
| 63 |  | 
| 64 | return 0; | 
| 65 |  | 
| 66 | } | 
| 67 |  | 
| 68 |  | 
| 69 | } | 
| 70 |  | 
| 71 | #endif |