zlaqsp()

subroutine zlaqsp	(	character	uplo,
		integer	n,
		complex*16, dimension( * )	ap,
		double precision, dimension( * )	s,
		double precision	scond,
		double precision	amax,
		character	equed )

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

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Purpose:

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

Parameters

[in]	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 !>
[in]	N	!> N is INTEGER !> The order of the matrix A. N >= 0. !>
[in,out]	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. !>
[in]	S	!> S is DOUBLE PRECISION array, dimension (N) !> The scale factors for A. !>
[in]	SCOND	!> SCOND is DOUBLE PRECISION !> Ratio of the smallest S(i) to the largest S(i). !>
[in]	AMAX	!> AMAX is DOUBLE PRECISION !> Absolute value of largest matrix entry. !>
[out]	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 = 'Y': Equilibration was done, i.e., A has been replaced by !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.