claqgb.f (3) Linux Manual Page

claqgb.f –

Synopsis

Functions/Subroutines

subroutine claqgb (M, N, KL, KU, AB, LDAB, R, C, ROWCND, COLCND, AMAX, EQUED)
CLAQGB scales a general band matrix, using row and column scaling factors computed by sgbequ.

Function/Subroutine Documentation

subroutine claqgb (integerM, integerN, integerKL, integerKU, complex, dimension( ldab, * )AB, integerLDAB, real, dimension( * )R, real, dimension( * )C, realROWCND, realCOLCND, realAMAX, characterEQUED)

CLAQGB scales a general band matrix, using row and column scaling factors computed by sgbequ.

Purpose:

 CLAQGB equilibrates a general M by N band matrix A with KL

 subdiagonals and KU superdiagonals using the row and scaling factors

 in the vectors R and C.

 

Parameters:

M

 M is INTEGER

 The number of rows of the matrix A. M >= 0.

N

 N is INTEGER

 The number of columns of the matrix A. N >= 0.

KL

 KL is INTEGER

 The number of subdiagonals within the band of A. KL >= 0.

KU

 KU is INTEGER

 The number of superdiagonals within the band of A. KU >= 0.

AB

 AB is COMPLEX array, dimension (LDAB,N)

 On entry, the matrix A in band storage, in rows 1 to KL+KU+1.

 The j-th column of A is stored in the j-th column of the

 array AB as follows:

 AB(ku+1+i-j,j) = A(i,j) for max(1,j-ku)<=i<=min(m,j+kl)

 On exit, the equilibrated matrix, in the same storage format

 as A. See EQUED for the form of the equilibrated matrix.

LDAB

 LDAB is INTEGER

 The leading dimension of the array AB. LDA >= KL+KU+1.

R

 R is REAL array, dimension (M)

 The row scale factors for A.

C

 C is REAL array, dimension (N)

 The column scale factors for A.

ROWCND

 ROWCND is REAL

 Ratio of the smallest R(i) to the largest R(i).

COLCND

 COLCND is REAL

 Ratio of the smallest C(i) to the largest C(i).

AMAX

 AMAX is REAL

 Absolute value of largest matrix entry.

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.

Date:

September 2012

Definition at line 160 of file claqgb.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.