linalg.h 1.81 KB
 Nicholas Breen committed Feb 01, 2019 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 ``````/* * Copyright 2009-2018 The VOTCA Development Team (http://www.votca.org) * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ #ifndef __VOTCA_TOOLS_LINALG_H #define __VOTCA_TOOLS_LINALG_H #include namespace votca { namespace tools { /** * \brief solves A*x=b under the constraint B*x = 0 * @param x storage for x * @param A matrix for linear equation system * @param b inhomogenity * @param constr constrained condition * * This function implements the qrsolver under constraints */ void linalg_constrained_qrsolve(Eigen::VectorXd &x, Eigen::MatrixXd &A, const Eigen::VectorXd &b, const Eigen::MatrixXd &constr); /** * \brief solves A*V=E*V for the first n eigenvalues * @param A symmetric matrix to diagonalize, is destroyed during iteration * @param E, eigenvalues * @param V, eigenvectors, each column is one eigenvector * @param nmax number of eigenvalues to return * * This function is only useful if MKL is used, wraps LAPACKE_ssyevx/LAPACKE_dsyevx */ bool linalg_eigenvalues(Eigen::MatrixXd&A, Eigen::VectorXd &E, Eigen::MatrixXd&V , int nmax ); bool linalg_eigenvalues(Eigen::MatrixXf&A, Eigen::VectorXf &E, Eigen::MatrixXf&V , int nmax ); }} #endif // __VOTCA_TOOLS_LINALG_H ``````