#include "blaswrap.h" /* zhst01.f -- translated by f2c (version 20061008). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib; on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */ #include "f2c.h" /* Table of constant values */ static doublecomplex c_b7 = {1.,0.}; static doublecomplex c_b8 = {0.,0.}; static doublecomplex c_b11 = {-1.,0.}; /* Subroutine */ int zhst01_(integer *n, integer *ilo, integer *ihi, doublecomplex *a, integer *lda, doublecomplex *h__, integer *ldh, doublecomplex *q, integer *ldq, doublecomplex *work, integer *lwork, doublereal *rwork, doublereal *result) { /* System generated locals */ integer a_dim1, a_offset, h_dim1, h_offset, q_dim1, q_offset; doublereal d__1, d__2; /* Local variables */ static doublereal eps, unfl, ovfl, anorm; extern /* Subroutine */ int zgemm_(char *, char *, integer *, integer *, integer *, doublecomplex *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, integer *), zunt01_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, doublereal *); static doublereal wnorm; extern /* Subroutine */ int dlabad_(doublereal *, doublereal *); extern doublereal dlamch_(char *), zlange_(char *, integer *, integer *, doublecomplex *, integer *, doublereal *); static integer ldwork; extern /* Subroutine */ int zlacpy_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *); static doublereal smlnum; /* -- LAPACK test routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= ZHST01 tests the reduction of a general matrix A to upper Hessenberg form: A = Q*H*Q'. Two test ratios are computed; RESULT(1) = norm( A - Q*H*Q' ) / ( norm(A) * N * EPS ) RESULT(2) = norm( I - Q'*Q ) / ( N * EPS ) The matrix Q is assumed to be given explicitly as it would be following ZGEHRD + ZUNGHR. In this version, ILO and IHI are not used, but they could be used to save some work if this is desired. Arguments ========= N (input) INTEGER The order of the matrix A. N >= 0. ILO (input) INTEGER IHI (input) INTEGER A is assumed to be upper triangular in rows and columns 1:ILO-1 and IHI+1:N, so Q differs from the identity only in rows and columns ILO+1:IHI. A (input) COMPLEX*16 array, dimension (LDA,N) The original n by n matrix A. LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,N). H (input) COMPLEX*16 array, dimension (LDH,N) The upper Hessenberg matrix H from the reduction A = Q*H*Q' as computed by ZGEHRD. H is assumed to be zero below the first subdiagonal. LDH (input) INTEGER The leading dimension of the array H. LDH >= max(1,N). Q (input) COMPLEX*16 array, dimension (LDQ,N) The orthogonal matrix Q from the reduction A = Q*H*Q' as computed by ZGEHRD + ZUNGHR. LDQ (input) INTEGER The leading dimension of the array Q. LDQ >= max(1,N). WORK (workspace) COMPLEX*16 array, dimension (LWORK) LWORK (input) INTEGER The length of the array WORK. LWORK >= 2*N*N. RWORK (workspace) DOUBLE PRECISION array, dimension (N) RESULT (output) DOUBLE PRECISION array, dimension (2) RESULT(1) = norm( A - Q*H*Q' ) / ( norm(A) * N * EPS ) RESULT(2) = norm( I - Q'*Q ) / ( N * EPS ) ===================================================================== Quick return if possible Parameter adjustments */ a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; h_dim1 = *ldh; h_offset = 1 + h_dim1; h__ -= h_offset; q_dim1 = *ldq; q_offset = 1 + q_dim1; q -= q_offset; --work; --rwork; --result; /* Function Body */ if (*n <= 0) { result[1] = 0.; result[2] = 0.; return 0; } unfl = dlamch_("Safe minimum"); eps = dlamch_("Precision"); ovfl = 1. / unfl; dlabad_(&unfl, &ovfl); smlnum = unfl * *n / eps; /* Test 1: Compute norm( A - Q*H*Q' ) / ( norm(A) * N * EPS ) Copy A to WORK */ ldwork = max(1,*n); zlacpy_(" ", n, n, &a[a_offset], lda, &work[1], &ldwork); /* Compute Q*H */ zgemm_("No transpose", "No transpose", n, n, n, &c_b7, &q[q_offset], ldq, &h__[h_offset], ldh, &c_b8, &work[ldwork * *n + 1], &ldwork); /* Compute A - Q*H*Q' */ zgemm_("No transpose", "Conjugate transpose", n, n, n, &c_b11, &work[ ldwork * *n + 1], &ldwork, &q[q_offset], ldq, &c_b7, &work[1], & ldwork); /* Computing MAX */ d__1 = zlange_("1", n, n, &a[a_offset], lda, &rwork[1]); anorm = max(d__1,unfl); wnorm = zlange_("1", n, n, &work[1], &ldwork, &rwork[1]); /* Note that RESULT(1) cannot overflow and is bounded by 1/(N*EPS) Computing MAX */ d__1 = smlnum, d__2 = anorm * eps; result[1] = min(wnorm,anorm) / max(d__1,d__2) / *n; /* Test 2: Compute norm( I - Q'*Q ) / ( N * EPS ) */ zunt01_("Columns", n, n, &q[q_offset], ldq, &work[1], lwork, &rwork[1], & result[2]); return 0; /* End of ZHST01 */ } /* zhst01_ */