LAPACK  3.4.2
LAPACK: Linear Algebra PACKage
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zlaqhp.f File Reference

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subroutine zlaqhp (UPLO, N, AP, S, SCOND, AMAX, EQUED)
 ZLAQHP scales a Hermitian matrix stored in packed form.

Function/Subroutine Documentation

subroutine zlaqhp ( character  UPLO,
integer  N,
complex*16, dimension( * )  AP,
double precision, dimension( * )  S,
double precision  SCOND,
double precision  AMAX,
character  EQUED 

ZLAQHP scales a Hermitian matrix stored in packed form.

Download ZLAQHP + dependencies [TGZ] [ZIP] [TXT]
 ZLAQHP equilibrates a Hermitian matrix A using the scaling factors
 in the vector S.
          UPLO is CHARACTER*1
          Specifies whether the upper or lower triangular part of the
          Hermitian matrix A is stored.
          = 'U':  Upper triangular
          = 'L':  Lower triangular
          N is INTEGER
          The order of the matrix A.  N >= 0.
          AP is COMPLEX*16 array, dimension (N*(N+1)/2)
          On entry, the upper or lower triangle of the Hermitian 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 is DOUBLE PRECISION array, dimension (N)
          The scale factors for A.
          Ratio of the smallest S(i) to the largest S(i).
          Absolute value of largest matrix entry.
          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          = 'Y':  Equilibration was done, i.e., A has been replaced by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.
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
September 2012

Definition at line 127 of file zlaqhp.f.

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