slaqge()

subroutine slaqge	(	integer	m,
		integer	n,
		real, dimension( lda, * )	a,
		integer	lda,
		real, dimension( * )	r,
		real, dimension( * )	c,
		real	rowcnd,
		real	colcnd,
		real	amax,
		character	equed )

SLAQGE scales a general rectangular matrix, using row and column scaling factors computed by sgeequ.

Download SLAQGE + dependencies [TGZ] [ZIP] [TXT]

Purpose:

!>
!> SLAQGE equilibrates a general M by N matrix A using the row and
!> column scaling factors in the vectors R and C.
!> 

Parameters

[in]	M	!> M is INTEGER !> The number of rows of the matrix A. M >= 0. !>
[in]	N	!> N is INTEGER !> The number of columns of the matrix A. N >= 0. !>
[in,out]	A	!> A is REAL array, dimension (LDA,N) !> On entry, the M by N matrix A. !> On exit, the equilibrated matrix. See EQUED for the form of !> the equilibrated matrix. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(M,1). !>
[in]	R	!> R is REAL array, dimension (M) !> The row scale factors for A. !>
[in]	C	!> C is REAL array, dimension (N) !> The column scale factors for A. !>
[in]	ROWCND	!> ROWCND is REAL !> Ratio of the smallest R(i) to the largest R(i). !>
[in]	COLCND	!> COLCND is REAL !> Ratio of the smallest C(i) to the largest C(i). !>
[in]	AMAX	!> AMAX is REAL !> Absolute value of largest matrix entry. !>
[out]	EQUED	!> EQUED is CHARACTER*1 !> Specifies the form of equilibration that was done. !> = 'N': No equilibration !> = 'R': Row equilibration, i.e., A has been premultiplied by !> diag(R). !> = 'C': Column equilibration, i.e., A has been postmultiplied !> by diag(C). !> = 'B': Both row and column equilibration, i.e., A has been !> replaced by diag(R) * A * diag(C). !>

Internal Parameters:

!>  THRESH is a threshold value used to decide if row or column scaling
!>  should be done based on the ratio of the row or column scaling
!>  factors.  If ROWCND < THRESH, row scaling is done, and if
!>  COLCND < THRESH, column scaling is done.
!>
!>  LARGE and SMALL are threshold values used to decide if row scaling
!>  should be done based on the absolute size of the largest matrix
!>  element.  If AMAX > LARGE or AMAX < SMALL, row scaling is done.
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.