ctpcon.f man page

ctpcon.f —

Synopsis

Functions/Subroutines

subroutine ctpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, RWORK, INFO)
CTPCON

Function/Subroutine Documentation

subroutine ctpcon (characterNORM, characterUPLO, characterDIAG, integerN, complex, dimension( * )AP, realRCOND, complex, dimension( * )WORK, real, dimension( * )RWORK, integerINFO)

CTPCON

Purpose:

CTPCON estimates the reciprocal of the condition number of a packed
triangular matrix A, in either the 1-norm or the infinity-norm.

The norm of A is computed and an estimate is obtained for
norm(inv(A)), then 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.

UPLO

UPLO is CHARACTER*1
= 'U':  A is upper triangular;
= 'L':  A is lower triangular.

DIAG

DIAG is CHARACTER*1
= 'N':  A is non-unit triangular;
= 'U':  A is unit triangular.

N

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

AP

AP is COMPLEX array, dimension (N*(N+1)/2)
The upper or lower triangular matrix A, packed columnwise in
a linear array.  The j-th column of A is stored in the array
AP as follows:
if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
If DIAG = 'U', the diagonal elements of A are not referenced
and are assumed to be 1.

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 (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

Definition at line 130 of file ctpcon.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

ctpcon(3) is an alias of ctpcon.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK