#include "blaswrap.h"
#include "f2c.h"

/* Subroutine */ int slaqsy_(char *uplo, integer *n, real *a, integer *lda, 
	real *s, real *scond, real *amax, char *equed)
{
/*  -- LAPACK auxiliary routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       February 29, 1992   


    Purpose   
    =======   

    SLAQSY equilibrates a symmetric 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   
            symmetric matrix A is stored.   
            = 'U':  Upper triangular   
            = 'L':  Lower triangular   

    N       (input) INTEGER   
            The order of the matrix A.  N >= 0.   

    A       (input/output) REAL array, dimension (LDA,N)   
            On entry, the symmetric 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            = 'Y':  Equilibration was done, i.e., A has been replaced by   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.   

    =====================================================================   


       Quick return if possible   

       Parameter adjustments */
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2;
    /* Local variables */
    static integer i__, j;
    static real large;
    extern logical lsame_(char *, char *);
    static real small, cj;
    extern doublereal slamch_(char *);
#define a_ref(a_1,a_2) a[(a_2)*a_dim1 + a_1]

    a_dim1 = *lda;
    a_offset = 1 + a_dim1 * 1;
    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;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    a_ref(i__, j) = cj * s[i__] * a_ref(i__, j);
/* L10: */
		}
/* L20: */
	    }
	} else {

/*           Lower triangle of A is stored. */

	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		cj = s[j];
		i__2 = *n;
		for (i__ = j; i__ <= i__2; ++i__) {
		    a_ref(i__, j) = cj * s[i__] * a_ref(i__, j);
/* L30: */
		}
/* L40: */
	    }
	}
	*(unsigned char *)equed = 'Y';
    }

    return 0;

/*     End of SLAQSY */

} /* slaqsy_ */

#undef a_ref



.