Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages

RedHat 9 (Linux i386) - man page for dgbcon (redhat section l)

DGBCON(l)					)					DGBCON(l)

NAME
       DGBCON  - estimate the reciprocal of the condition number of a real general band matrix A,
       in either the 1-norm or the infinity-norm,

SYNOPSIS
       SUBROUTINE DGBCON( NORM, N, KL, KU, AB, LDAB, IPIV, ANORM, RCOND, WORK, IWORK, INFO )

	   CHARACTER	  NORM

	   INTEGER	  INFO, KL, KU, LDAB, N

	   DOUBLE	  PRECISION ANORM, RCOND

	   INTEGER	  IPIV( * ), IWORK( * )

	   DOUBLE	  PRECISION AB( LDAB, * ), WORK( * )

PURPOSE
       DGBCON estimates the reciprocal of the condition number of a real general band  matrix  A,
       in either the 1-norm or the infinity-norm, using the LU factorization computed by DGBTRF.

       An  estimate  is  obtained for norm(inv(A)), and the reciprocal of the condition number is
       computed as
	  RCOND = 1 / ( norm(A) * norm(inv(A)) ).

ARGUMENTS
       NORM    (input) CHARACTER*1
	       Specifies whether the 1-norm condition number or the infinity-norm condition  num-
	       ber is required:
	       = '1' or 'O':  1-norm;
	       = 'I':	      Infinity-norm.

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.

       KL      (input) INTEGER
	       The number of subdiagonals within the band of A.  KL >= 0.

       KU      (input) INTEGER
	       The number of superdiagonals within the band of A.  KU >= 0.

       AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
	       Details of the LU factorization of the band matrix A, as computed by DGBTRF.  U is
	       stored as an upper triangular band matrix with KL+KU superdiagonals in rows  1  to
	       KL+KU+1,  and  the  multipliers	used  during the factorization are stored in rows
	       KL+KU+2 to 2*KL+KU+1.

       LDAB    (input) INTEGER
	       The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.

       IPIV    (input) INTEGER array, dimension (N)
	       The pivot indices; for 1 <= i <= N, row i of the matrix was interchanged with  row
	       IPIV(i).

       ANORM   (input) DOUBLE PRECISION
	       If  NORM  =  '1'  or 'O', the 1-norm of the original matrix A.  If NORM = 'I', the
	       infinity-norm of the original matrix A.

       RCOND   (output) DOUBLE PRECISION
	       The reciprocal of the condition number of  the  matrix  A,  computed  as  RCOND	=
	       1/(norm(A) * norm(inv(A))).

       WORK    (workspace) DOUBLE PRECISION array, dimension (3*N)

       IWORK   (workspace) INTEGER array, dimension (N)

       INFO    (output) INTEGER
	       = 0:  successful exit
	       < 0: if INFO = -i, the i-th argument had an illegal value

LAPACK version 3.0			   15 June 2000 				DGBCON(l)


All times are GMT -4. The time now is 12:21 PM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
UNIX.COM Login
Username:
Password:  
Show Password