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zlaqgb.f(3) LAPACK zlaqgb.f(3)

zlaqgb.f -


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

ZLAQGB scales a general band matrix, using row and column scaling factors computed by sgbequ.
Purpose:
 ZLAQGB 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*16 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 DOUBLE PRECISION array, dimension (M)
          The row scale factors for A.
C
          C is DOUBLE PRECISION array, dimension (N)
          The column scale factors for A.
ROWCND
          ROWCND is DOUBLE PRECISION
          Ratio of the smallest R(i) to the largest R(i).
COLCND
          COLCND is DOUBLE PRECISION
          Ratio of the smallest C(i) to the largest C(i).
AMAX
          AMAX is DOUBLE PRECISION
          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          = 'B':  Both row and column equilibration, i.e., A has been
                  replaced by diag(R) * A * diag(C).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 zlaqgb.f.

Generated automatically by Doxygen for LAPACK from the source code.
Sat Nov 16 2013 Version 3.4.2

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