claqhb()

subroutine claqhb	(	character	uplo,
		integer	n,
		integer	kd,
		complex, dimension( ldab, * )	ab,
		integer	ldab,
		real, dimension( * )	s,
		real	scond,
		real	amax,
		character	equed )

CLAQHB scales a Hermitian band matrix, using scaling factors computed by cpbequ.

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Purpose:

!>
!> CLAQHB equilibrates an Hermitian band 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]	KD	!> KD is INTEGER !> The number of super-diagonals of the matrix A if UPLO = 'U', !> or the number of sub-diagonals if UPLO = 'L'. KD >= 0. !>
[in,out]	AB	!> AB is COMPLEX array, dimension (LDAB,N) !> On entry, the upper or lower triangle of the symmetric band !> matrix A, stored in the first KD+1 rows of the array. The !> j-th column of A is stored in the j-th column of the array AB !> as follows: !> if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; !> if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). !> !> On exit, if INFO = 0, the triangular factor U or L from the !> Cholesky factorization A = U**H *U or A = L*L**H of the band !> matrix A, in the same storage format as A. !>
[in]	LDAB	!> LDAB is INTEGER !> The leading dimension of the array AB. LDAB >= KD+1. !>
[out]	S	!> S is REAL array, dimension (N) !> The scale factors for A. !>
[in]	SCOND	!> SCOND is REAL !> Ratio of the smallest S(i) to the largest S(i). !>
[in]	AMAX	!> AMAX is REAL !> 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 = 'Y': Equilibration was done, i.e., A has been replaced by !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.