# cspcon.f(3) [centos man page]

```cspcon.f(3)							      LAPACK							       cspcon.f(3)

NAME
cspcon.f -

SYNOPSIS
Functions/Subroutines
subroutine cspcon (UPLO, N, AP, IPIV, ANORM, RCOND, WORK, INFO)
CSPCON

Function/Subroutine Documentation
subroutine cspcon (characterUPLO, integerN, complex, dimension( * )AP, integer, dimension( * )IPIV, realANORM, realRCOND, complex, dimension( *
)WORK, integerINFO)
CSPCON

Purpose:

CSPCON estimates the reciprocal of the condition number (in the
1-norm) of a complex symmetric packed matrix A using the
factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF.

An estimate is obtained for norm(inv(A)), and the reciprocal of the
condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

Parameters:
UPLO

UPLO is CHARACTER*1
Specifies whether the details of the factorization are stored
as an upper or lower triangular matrix.
= 'U':  Upper triangular, form is A = U*D*U**T;
= 'L':  Lower triangular, form is A = L*D*L**T.

N

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

AP

AP is COMPLEX array, dimension (N*(N+1)/2)
The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by CSPTRF, stored as a
packed triangular matrix.

IPIV

IPIV is INTEGER array, dimension (N)
Details of the interchanges and the block structure of D
as determined by CSPTRF.

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 an
estimate of the 1-norm of inv(A) computed in this routine.

WORK

WORK is COMPLEX 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

NAG Ltd.

Date:
November 2011

Definition at line 119 of file cspcon.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       cspcon.f(3)```

## Check Out this Related Man Page

```CSPCON(l)								 )								 CSPCON(l)

NAME
CSPCON - estimate the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A =
U*D*U**T or A = L*D*L**T computed by CSPTRF

SYNOPSIS
SUBROUTINE CSPCON( UPLO, N, AP, IPIV, ANORM, RCOND, WORK, INFO )

CHARACTER	  UPLO

INTEGER	  INFO, N

REAL 	  ANORM, RCOND

INTEGER	  IPIV( * )

COMPLEX	  AP( * ), WORK( * )

PURPOSE
CSPCON estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric packed matrix A using the factorization A  =
U*D*U**T  or A = L*D*L**T computed by CSPTRF.  An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is com-
puted as RCOND = 1 / (ANORM * norm(inv(A))).

ARGUMENTS
UPLO    (input) CHARACTER*1
Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.  =  'U':	Upper  triangular,
form is A = U*D*U**T;
= 'L':  Lower triangular, form is A = L*D*L**T.

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

AP      (input) COMPLEX array, dimension (N*(N+1)/2)
The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CSPTRF, stored as a packed triangu-
lar matrix.

IPIV    (input) INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as determined by CSPTRF.

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

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

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

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

LAPACK version 3.0						   15 June 2000 							 CSPCON(l)```
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