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  • 12/20/2021
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LAPACKE_zheevx 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_zheevx Example. ======================= Program computes eigenvalues specified by a selected range of values and corresponding eigenvectors of a complex Hermitian matrix A: ( 6.51, 0.00) ( -5.92, 9.53) ( -2.46, 2.91) ( 8.84, 3.21) ( -5.92, -9.53) ( -1.73, 0.00) ( 6.50, 2.09) ( 1.32, 8.81) ( -2.46, -2.91) ( 6.50, -2.09) ( 6.90, 0.00) ( -0.59, 2.47) ( 8.84, -3.21) ( 1.32, -8.81) ( -0.59, -2.47) ( -2.85, 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_zheevx (column-major, high-level) Example Program Results The total number of eigenvalues found: 3 Selected eigenvalues 0.09 9.53 18.75 Selected eigenvectors (stored columnwise) ( 0.18, 0.00) ( -0.54, 0.00) ( 0.67, 0.00) ( -0.40, -0.31) ( -0.21, -0.17) ( -0.30, -0.43) ( 0.60, 0.40) ( -0.35, -0.28) ( -0.39, -0.34) ( -0.34, 0.26) ( -0.57, 0.35) ( 0.05, 0.05) */ #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 ifail[N]; double w[N]; MKL_Complex16 z[LDZ*N]; MKL_Complex16 a[LDA*N] = { { 6.51, 0.00}, {-5.92, -9.53}, {-2.46, -2.91}, { 8.84, -3.21}, { 0.00, 0.00}, {-1.73, 0.00}, { 6.50, -2.09}, { 1.32, -8.81}, { 0.00, 0.00}, { 0.00, 0.00}, { 6.90, 0.00}, {-0.59, -2.47}, { 0.00, 0.00}, { 0.00, 0.00}, { 0.00, 0.00}, {-2.85, 0.00} }; /* Executable statements */ printf( "LAPACKE_zheevx (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 = 0.0; vu = 100.0; /* Solve eigenproblem */ info = LAPACKE_zheevx( LAPACK_COL_MAJOR, 'V', 'V', 'L', n, a, lda, vl, vu, il, iu, abstol, &m, w, z, ldz, ifail ); /* 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_zheevx 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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