redhat man page for zgeequ

Query: zgeequ

OS: redhat

Section: l

Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar

ZGEEQU(l)								 )								 ZGEEQU(l)

NAME
ZGEEQU - compute row and column scalings intended to equilibrate an M-by-N matrix A and reduce its condition number
SYNOPSIS
SUBROUTINE ZGEEQU( M, N, A, LDA, R, C, ROWCND, COLCND, AMAX, INFO ) INTEGER INFO, LDA, M, N DOUBLE PRECISION AMAX, COLCND, ROWCND DOUBLE PRECISION C( * ), R( * ) COMPLEX*16 A( LDA, * )
PURPOSE
ZGEEQU computes row and column scalings intended to equilibrate an M-by-N matrix A and reduce its condition number. R returns the row scale factors and C the column scale factors, chosen to try to make the largest element in each row and column of the matrix B with elements B(i,j)=R(i)*A(i,j)*C(j) have absolute value 1. R(i) and C(j) are restricted to be between SMLNUM = smallest safe number and BIGNUM = largest safe number. Use of these scaling factors is not guaranteed to reduce the condition number of A but works well in practice.
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) COMPLEX*16 array, dimension (LDA,N) The M-by-N matrix whose equilibration factors are to be computed. LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,M). R (output) DOUBLE PRECISION array, dimension (M) If INFO = 0 or INFO > M, R contains the row scale factors for A. C (output) DOUBLE PRECISION array, dimension (N) If INFO = 0, C contains the column scale factors for A. ROWCND (output) DOUBLE PRECISION If INFO = 0 or INFO > M, ROWCND contains the ratio of the smallest R(i) to the largest R(i). If ROWCND >= 0.1 and AMAX is neither too large nor too small, it is not worth scaling by R. COLCND (output) DOUBLE PRECISION If INFO = 0, COLCND contains the ratio of the smallest C(i) to the largest C(i). If COLCND >= 0.1, it is not worth scaling by C. AMAX (output) DOUBLE PRECISION Absolute value of largest matrix element. If AMAX is very close to overflow or very close to underflow, the matrix should be scaled. INFO (output) INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: if INFO = i, and i is <= M: the i-th row of A is exactly zero > M: the (i-M)-th column of A is exactly zero LAPACK version 3.0 15 June 2000 ZGEEQU(l)
Related Man Pages
sgeequ(l) - redhat
dgeequ(3) - debian
zgeequ(3) - debian
dgeequ.f(3) - debian
zgeequ.f(3) - debian
Similar Topics in the Unix Linux Community
largest file
list largest files
Find smallest &amp; largest in every column
Problem to print out record got smallest number in specific column
Filter file with condition