cgecon.f man page

cgecon.f

Synopsis

Functions/Subroutines

subroutine cgecon (NORM, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO)
CGECON

Function/Subroutine Documentation

subroutine cgecon (character NORM, integer N, complex, dimension( lda, * ) A, integer LDA, real ANORM, real RCOND, complex, dimension( * ) WORK, real, dimension( * ) RWORK, integer INFO)

CGECON  

Purpose:

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

 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)) ).
Parameters:

NORM

          NORM is 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

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

A

          A is COMPLEX array, dimension (LDA,N)
          The factors L and U from the factorization A = P*L*U
          as computed by CGETRF.

LDA

          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).

ANORM

          ANORM is 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

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

WORK

          WORK is COMPLEX array, dimension (2*N)

RWORK

          RWORK is REAL array, dimension (2*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:

December 2016

Definition at line 126 of file cgecon.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page cgecon(3) is an alias of cgecon.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK