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

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

Function/Subroutine Documentation

subroutine claqhp ( character  UPLO,
integer  N,
complex, dimension( * )  AP,
real, dimension( * )  S,
real  SCOND,
real  AMAX,
character  EQUED 

CLAQHP scales a Hermitian matrix stored in packed form.

Download CLAQHP + dependencies [TGZ] [ZIP] [TXT]
 CLAQHP 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 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 REAL array, dimension (N)
          The scale factors for A.
          SCOND is REAL
          Ratio of the smallest S(i) to the largest S(i).
          AMAX is REAL
          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          = 'Y':  Equilibration was done, i.e., A has been replaced by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 claqhp.f.

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