cgbcon man page on IRIX

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CGBCON(3F)							    CGBCON(3F)

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

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

	 CHARACTER	NORM

	 INTEGER	INFO, KL, KU, LDAB, N

	 REAL		ANORM, RCOND

	 INTEGER	IPIV( * )

	 REAL		RWORK( * )

	 COMPLEX	AB( LDAB, * ), WORK( * )

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

     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 number 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) COMPLEX array, dimension (LDAB,N)
	     Details of the LU factorization of the band matrix A, as computed
	     by CGBTRF.	 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.

									Page 1

CGBCON(3F)							    CGBCON(3F)

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

     WORK    (workspace) COMPLEX array, dimension (2*N)

     RWORK   (workspace) REAL array, dimension (N)

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

									Page 2

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