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NAME
     dlaqsp - equilibrate a symmetric matrix A using the  scaling
     factors in the vector S

SYNOPSIS
     SUBROUTINE DLAQSP( UPLO, N, AP, S, SCOND, AMAX, EQUED )

     CHARACTER EQUED, UPLO

     INTEGER N

     DOUBLE PRECISION AMAX, SCOND

     DOUBLE PRECISION AP( * ), S( * )



     #include <sunperf.h>

     void dlaqsp(char uplo, int n, double *dap, double *s, double
               scond, double amax, char *equed) ;

PURPOSE
     DLAQSP 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.

     AP        (input/output) DOUBLE PRECISION  array,  dimension
               (N*(N+1)/2)
               On entry, the upper or lower triangle of the  sym-
               metric  matrix  A,  packed  columnwise in a linear
               array.  The j-th column of  A  is  stored  in  the
               array  AP  as  follows:  if UPLO = 'U', AP(i + (j-
               1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L',  AP(i
               + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.

               On exit, the equilibrated matrix:  diag(S) *  A  *
               diag(S), in the same storage format as A.

     S         (input) DOUBLE PRECISION array, dimension (N)
               The scale factors for A.

     SCOND     (input) DOUBLE PRECISION
               Ratio of the smallest S(i) to the largest S(i).

     AMAX      (input) DOUBLE PRECISION
               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               = 'Y':  Equilibration was done, i.e., A  has  been
               replaced by diag(S) * A * diag(S).

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 scal-
     ing should be done based on the absolute size of the largest
     matrix element.  If AMAX > LARGE or AMAX < SMALL, scaling is
     done.

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