CLAQGE(l) ) CLAQGE(l)NAME
CLAQGE - equilibrate a general M by N matrix A using the row and scal‐
ing factors in the vectors R and C
SYNOPSIS
SUBROUTINE CLAQGE( M, N, A, LDA, R, C, ROWCND, COLCND, AMAX, EQUED )
CHARACTER EQUED
INTEGER LDA, M, N
REAL AMAX, COLCND, ROWCND
REAL C( * ), R( * )
COMPLEX A( LDA, * )
PURPOSE
CLAQGE equilibrates a general M by N matrix A using the row and scaling
factors in the vectors R and C.
ARGUMENTS
M (input) INTEGER
The number of rows of the matrix A. M >= 0.
N (input) INTEGER
The number of columns of the matrix A. N >= 0.
A (input/output) COMPLEX 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.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(M,1).
R (input) REAL array, dimension (M)
The row scale factors for A.
C (input) REAL array, dimension (N)
The column scale factors for A.
ROWCND (input) REAL
Ratio of the smallest R(i) to the largest R(i).
COLCND (input) REAL
Ratio of the smallest C(i) to the largest C(i).
AMAX (input) REAL
Absolute value of largest matrix entry.
EQUED (output) 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 post‐
multiplied by diag(C). = 'B': Both row and column equilibra‐
tion, i.e., A has been replaced by diag(R) * A * diag(C).
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 ele‐
ment. If AMAX > LARGE or AMAX < SMALL, row scaling is done.
LAPACK version 3.0 15 June 2000 CLAQGE(l)
