Unix/Linux Go Back    


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

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


ZPTCON(l)					)					ZPTCON(l)

NAME
       ZPTCON  - compute the reciprocal of the condition number (in the 1-norm) of a complex Her-
       mitian positive definite tridiagonal matrix using the factorization A = L*D*L**H  or  A	=
       U**H*D*U computed by ZPTTRF

SYNOPSIS
       SUBROUTINE ZPTCON( N, D, E, ANORM, RCOND, RWORK, INFO )

	   INTEGER	  INFO, N

	   DOUBLE	  PRECISION ANORM, RCOND

	   DOUBLE	  PRECISION D( * ), RWORK( * )

	   COMPLEX*16	  E( * )

PURPOSE
       ZPTCON  computes  the reciprocal of the condition number (in the 1-norm) of a complex Her-
       mitian positive definite tridiagonal matrix using the factorization A = L*D*L**H  or  A	=
       U**H*D*U  computed by ZPTTRF.  Norm(inv(A)) is computed by a direct method, and the recip-
       rocal of the condition number is computed as
			RCOND = 1 / (ANORM * norm(inv(A))).

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

       D       (input) DOUBLE PRECISION array, dimension (N)
	       The n diagonal elements of the diagonal matrix D from the factorization of  A,  as
	       computed by ZPTTRF.

       E       (input) COMPLEX*16 array, dimension (N-1)
	       The (n-1) off-diagonal elements of the unit bidiagonal factor U or L from the fac-
	       torization of A, as computed by ZPTTRF.

       ANORM   (input) DOUBLE PRECISION
	       The 1-norm of the original matrix A.

       RCOND   (output) DOUBLE PRECISION
	       The reciprocal of the condition number of  the  matrix  A,  computed  as  RCOND	=
	       1/(ANORM * AINVNM), where AINVNM is the 1-norm of inv(A) computed in this routine.

       RWORK   (workspace) DOUBLE PRECISION array, dimension (N)

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

FURTHER DETAILS
       The  method  used  is described in Nicholas J. Higham, "Efficient Algorithms for Computing
       the Condition Number of a Tridiagonal Matrix", SIAM J. Sci. Stat. Comput., Vol. 7, No.  1,
       January 1986.

LAPACK version 3.0			   15 June 2000 				ZPTCON(l)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 03:09 PM.