debian man page for sptcon

sptcon.f(3)							      LAPACK							       sptcon.f(3)

NAME
       sptcon.f -

SYNOPSIS
   Functions/Subroutines
       subroutine sptcon (N, D, E, ANORM, RCOND, WORK, INFO)
	   SPTCON

Function/Subroutine Documentation
   subroutine sptcon (integerN, real, dimension( * )D, real, dimension( * )E, realANORM, realRCOND, real, dimension( * )WORK, integerINFO)
       SPTCON

       Purpose:

	    SPTCON computes the reciprocal of the condition number (in the
	    1-norm) of a real symmetric positive definite tridiagonal matrix
	    using the factorization A = L*D*L**T or A = U**T*D*U computed by
	    SPTTRF.

	    Norm(inv(A)) is computed by a direct method, and the reciprocal of
	    the condition number is computed as
			 RCOND = 1 / (ANORM * norm(inv(A))).

       Parameters:
	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   D

		     D is REAL array, dimension (N)
		     The n diagonal elements of the diagonal matrix D from the
		     factorization of A, as computed by SPTTRF.

	   E

		     E is REAL array, dimension (N-1)
		     The (n-1) off-diagonal elements of the unit bidiagonal factor
		     U or L from the factorization of A,  as computed by SPTTRF.

	   ANORM

		     ANORM is REAL
		     The 1-norm of the original matrix A.

	   RCOND

		     RCOND is REAL
		     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.

	   WORK

		     WORK is REAL array, dimension (N)

	   INFO

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

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       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.

       Definition at line 119 of file sptcon.f.

Author
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Version 3.4.1							  Sun May 26 2013						       sptcon.f(3)