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/* claqhe.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"
#include "blaswrap.h"
/* Subroutine */ int claqhe_(char *uplo, integer *n, complex *a, integer *lda,
real *s, real *scond, real *amax, char *equed)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
real r__1;
complex q__1;
/* Local variables */
integer i__, j;
real cj, large;
extern logical lsame_(char *, char *);
real small;
extern doublereal slamch_(char *);
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CLAQHE equilibrates a Hermitian matrix A using the scaling factors */
/* in the vector S. */
/* Arguments */
/* ========= */
/* UPLO (input) CHARACTER*1 */
/* Specifies whether the upper or lower triangular part of the */
/* Hermitian matrix A is stored. */
/* = 'U': Upper triangular */
/* = 'L': Lower triangular */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA,N) */
/* On entry, the Hermitian matrix A. If UPLO = 'U', the leading */
/* n by n upper triangular part of A contains the upper */
/* triangular part of the matrix A, and the strictly lower */
/* triangular part of A is not referenced. If UPLO = 'L', the */
/* leading n by n lower triangular part of A contains the lower */
/* triangular part of the matrix A, and the strictly upper */
/* triangular part of A is not referenced. */
/* On exit, if EQUED = 'Y', the equilibrated matrix: */
/* diag(S) * A * diag(S). */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(N,1). */
/* S (input) REAL array, dimension (N) */
/* The scale factors for A. */
/* SCOND (input) REAL */
/* Ratio of the smallest S(i) to the largest S(i). */
/* AMAX (input) REAL */
/* Absolute value of largest matrix entry. */
/* EQUED (output) CHARACTER*1 */
/* Specifies whether or not equilibration was done. */
/* = 'N': No equilibration. */
/* = 'Y': Equilibration was done, i.e., A has been replaced by */
/* diag(S) * A * diag(S). */
/* Internal Parameters */
/* =================== */
/* THRESH is a threshold value used to decide if scaling should be done */
/* based on the ratio of the scaling factors. If SCOND < THRESH, */
/* scaling is done. */
/* LARGE and SMALL are threshold values used to decide if scaling should */
/* be done based on the absolute size of the largest matrix element. */
/* If AMAX > LARGE or AMAX < SMALL, scaling is done. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Quick return if possible */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--s;
/* Function Body */
if (*n <= 0) {
*(unsigned char *)equed = 'N';
return 0;
}
/* Initialize LARGE and SMALL. */
small = slamch_("Safe minimum") / slamch_("Precision");
large = 1.f / small;
if (*scond >= .1f && *amax >= small && *amax <= large) {
/* No equilibration */
*(unsigned char *)equed = 'N';
} else {
/* Replace A by diag(S) * A * diag(S). */
if (lsame_(uplo, "U")) {
/* Upper triangle of A is stored. */
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
cj = s[j];
i__2 = j - 1;
for (i__ = 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
r__1 = cj * s[i__];
i__4 = i__ + j * a_dim1;
q__1.r = r__1 * a[i__4].r, q__1.i = r__1 * a[i__4].i;
a[i__3].r = q__1.r, a[i__3].i = q__1.i;
/* L10: */
}
i__2 = j + j * a_dim1;
i__3 = j + j * a_dim1;
r__1 = cj * cj * a[i__3].r;
a[i__2].r = r__1, a[i__2].i = 0.f;
/* L20: */
}
} else {
/* Lower triangle of A is stored. */
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
cj = s[j];
i__2 = j + j * a_dim1;
i__3 = j + j * a_dim1;
r__1 = cj * cj * a[i__3].r;
a[i__2].r = r__1, a[i__2].i = 0.f;
i__2 = *n;
for (i__ = j + 1; i__ <= i__2; ++i__) {
i__3 = i__ + j * a_dim1;
r__1 = cj * s[i__];
i__4 = i__ + j * a_dim1;
q__1.r = r__1 * a[i__4].r, q__1.i = r__1 * a[i__4].i;
a[i__3].r = q__1.r, a[i__3].i = q__1.i;
/* L30: */
}
/* L40: */
}
}
*(unsigned char *)equed = 'Y';
}
return 0;
/* End of CLAQHE */
} /* claqhe_ */
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