zlaqsp.f(3)

NAME
zlaqsp.f -

SYNOPSIS

  Functions/Subroutines
subroutine zlaqsp (UPLO, N, AP, S, SCOND, AMAX, EQUED)
ZLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.

Function/Subroutine Documentation

  subroutine zlaqsp (characterUPLO, integerN, complex*16, dimension( * )AP, double precision, dimension( * )S, double precisionSCOND, double precisionAMAX, characterEQUED)

ZLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.

Purpose:

     ZLAQSP equilibrates a symmetric matrix A using the scaling factors
     in the vector S.

Parameters:
    UPLO

              UPLO is CHARACTER*1
              Specifies whether the upper or lower triangular part of the
              symmetric matrix A is stored.
              = 'U':  Upper triangular
              = 'L':  Lower triangular

    N

              N is INTEGER
              The order of the matrix A.  N >= 0.

    AP

              AP is COMPLEX*16 array, dimension (N*(N+1)/2)
              On entry, the upper or lower triangle of the symmetric 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

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

    SCOND

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

    AMAX

              AMAX is DOUBLE PRECISION
              Absolute value of largest matrix entry.

    EQUED

              EQUED is 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              = 'Y':  Equilibration was done, i.e., A has been replaced by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.

Author:
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Date:
    September 2012

Definition at line 127 of file zlaqsp.f.

Author

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