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  • 12/20/2021
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LAPACKE_zheevr Example Program in C for Column Major Data Layout

/******************************************************************************* * Copyright (C) 2009-2015 Intel Corporation. All Rights Reserved. * The information and material ("Material") provided below is owned by Intel * Corporation or its suppliers or licensors, and title to such Material remains * with Intel Corporation or its suppliers or licensors. The Material contains * proprietary information of Intel or its suppliers and licensors. The Material * is protected by worldwide copyright laws and treaty provisions. No part of * the Material may be copied, reproduced, published, uploaded, posted, * transmitted, or distributed in any way without Intel's prior express written * permission. No license under any patent, copyright or other intellectual * property rights in the Material is granted to or conferred upon you, either * expressly, by implication, inducement, estoppel or otherwise. Any license * under such intellectual property rights must be express and approved by Intel * in writing. * ******************************************************************************** */ /* LAPACKE_zheevr Example. ======================= Program computes eigenvalues specified by a selected range of values and corresponding eigenvectors of a complex Hermitian matrix A using the Relatively Robust Representations, where A is: ( -2.16, 0.00) ( -0.16, -4.86) ( -7.23, -9.38) ( -0.04, 6.86) ( -0.16, 4.86) ( 7.45, 0.00) ( 4.39, 6.29) ( -8.11, -4.41) ( -7.23, 9.38) ( 4.39, -6.29) ( -9.03, 0.00) ( -6.89, -7.66) ( -0.04, -6.86) ( -8.11, 4.41) ( -6.89, 7.66) ( 7.76, 0.00) Description. ============ The routine computes selected eigenvalues and, optionally, eigenvectors of an n-by-n complex Hermitian matrix A. The eigenvector v(j) of A satisfies A*v(j) = lambda(j)*v(j) where lambda(j) is its eigenvalue. The computed eigenvectors are orthonormal. Eigenvalues and eigenvectors can be selected by specifying either a range of values or a range of indices for the desired eigenvalues. Example Program Results. ======================== LAPACKE_zheevr (column-major, high-level) Example Program Results The total number of eigenvalues found: 2 Selected eigenvalues -4.18 3.57 Selected eigenvectors (stored columnwise) ( 0.68, 0.00) ( 0.38, 0.00) ( 0.03, 0.18) ( 0.54, -0.57) ( -0.03, 0.21) ( -0.40, 0.04) ( 0.20, 0.64) ( -0.14, -0.26) */ #include <stdlib.h> #include <stdio.h> #include "mkl_lapacke.h" /* Auxiliary routines prototypes */ extern void print_matrix( char* desc, MKL_INT m, MKL_INT n, MKL_Complex16* a, MKL_INT lda ); extern void print_rmatrix( char* desc, MKL_INT m, MKL_INT n, double* a, MKL_INT lda ); /* Parameters */ #define N 4 #define LDA N #define LDZ N /* Main program */ int main() { /* Locals */ MKL_INT n = N, lda = LDA, ldz = LDZ, il, iu, m, info; double abstol, vl, vu; /* Local arrays */ MKL_INT isuppz[N]; double w[N]; MKL_Complex16 z[LDZ*N]; MKL_Complex16 a[LDA*N] = { {-2.16, 0.00}, {-0.16, 4.86}, {-7.23, 9.38}, {-0.04, -6.86}, { 0.00, 0.00}, { 7.45, 0.00}, { 4.39, -6.29}, {-8.11, 4.41}, { 0.00, 0.00}, { 0.00, 0.00}, {-9.03, 0.00}, {-6.89, 7.66}, { 0.00, 0.00}, { 0.00, 0.00}, { 0.00, 0.00}, { 7.76, 0.00} }; /* Executable statements */ printf( "LAPACKE_zheevr (column-major, high-level) Example Program Results\n" ); /* Negative abstol means using the default value */ abstol = -1.0; /* Set VL, VU to compute eigenvalues in half-open (VL,VU] interval */ vl = -5.0; vu = 5.0; /* Solve eigenproblem */ info = LAPACKE_zheevr( LAPACK_COL_MAJOR, 'V', 'V', 'L', n, a, lda, vl, vu, il, iu, abstol, &m, w, z, ldz, isuppz ); /* Check for convergence */ if( info > 0 ) { printf( "The algorithm failed to compute eigenvalues.\n" ); exit( 1 ); } /* Print the number of eigenvalues found */ printf( "\n The total number of eigenvalues found:%2i\n", m ); /* Print eigenvalues */ print_rmatrix( "Selected eigenvalues", 1, m, w, 1 ); /* Print eigenvectors */ print_matrix( "Selected eigenvectors (stored columnwise)", n, m, z, ldz ); exit( 0 ); } /* End of LAPACKE_zheevr Example */ /* Auxiliary routine: printing a matrix */ void print_matrix( char* desc, MKL_INT m, MKL_INT n, MKL_Complex16* a, MKL_INT lda ) { MKL_INT i, j; printf( "\n %s\n", desc ); for( i = 0; i < m; i++ ) { for( j = 0; j < n; j++ ) printf( " (%6.2f,%6.2f)", a[i+j*lda].real, a[i+j*lda].imag ); printf( "\n" ); } } /* Auxiliary routine: printing a real matrix */ void print_rmatrix( char* desc, MKL_INT m, MKL_INT n, double* a, MKL_INT lda ) { MKL_INT i, j; printf( "\n %s\n", desc ); for( i = 0; i < m; i++ ) { for( j = 0; j < n; j++ ) printf( " %6.2f", a[i+j*lda] ); printf( "\n" ); } }

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