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

```dla_syrcond.f(3)						      LAPACK							  dla_syrcond.f(3)

NAME
dla_syrcond.f -

SYNOPSIS
Functions/Subroutines
DOUBLE PRECISION function dla_syrcond (UPLO, N, A, LDA, AF, LDAF, IPIV, CMODE, C, INFO, WORK, IWORK)
DLA_SYRCOND estimates the Skeel condition number for a symmetric indefinite matrix.

Function/Subroutine Documentation
DOUBLE PRECISION function dla_syrcond (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, double precision,
dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, integerCMODE, double precision, dimension( * )C, integerINFO, double
precision, dimension( * )WORK, integer, dimension( * )IWORK)
DLA_SYRCOND estimates the Skeel condition number for a symmetric indefinite matrix.

Purpose:

DLA_SYRCOND estimates the Skeel condition number of  op(A) * op2(C)
where op2 is determined by CMODE as follows
CMODE =	1    op2(C) = C
CMODE =	0    op2(C) = I
CMODE = -1    op2(C) = inv(C)
The Skeel condition number cond(A) = norminf( |inv(A)||A| )
is computed by computing scaling factors R such that
diag(R)*A*op2(C) is row equilibrated and computing the standard
infinity-norm condition number.

Parameters:
UPLO

UPLO is CHARACTER*1
= 'U':  Upper triangle of A is stored;
= 'L':  Lower triangle of A is stored.

N

N is INTEGER
The number of linear equations, i.e., the order of the
matrix A.  N >= 0.

A

A is DOUBLE PRECISION array, dimension (LDA,N)
On entry, the N-by-N matrix A.

LDA

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

AF

AF is DOUBLE PRECISION array, dimension (LDAF,N)
The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by DSYTRF.

LDAF

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

IPIV

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

CMODE

CMODE is INTEGER
Determines op2(C) in the formula op(A) * op2(C) as follows:
CMODE =  1    op2(C) = C
CMODE =  0    op2(C) = I
CMODE = -1    op2(C) = inv(C)

C

C is DOUBLE PRECISION array, dimension (N)
The vector C in the formula op(A) * op2(C).

INFO

INFO is INTEGER
= 0:	Successful exit.
i > 0:	The ith argument is invalid.

WORK

WORK is DOUBLE PRECISION array, dimension (3*N).
Workspace.

IWORK

IWORK is INTEGER array, dimension (N).
Workspace.

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
September 2012

Definition at line 147 of file dla_syrcond.f.

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

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

## Check Out this Related Man Page

```dla_gercond.f(3)						      LAPACK							  dla_gercond.f(3)

NAME
dla_gercond.f -

SYNOPSIS
Functions/Subroutines
DOUBLE PRECISION function dla_gercond (TRANS, N, A, LDA, AF, LDAF, IPIV, CMODE, C, INFO, WORK, IWORK)
DLA_GERCOND estimates the Skeel condition number for a general matrix.

Function/Subroutine Documentation
DOUBLE PRECISION function dla_gercond (characterTRANS, integerN, double precision, dimension( lda, * )A, integerLDA, double precision,
dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, integerCMODE, double precision, dimension( * )C, integerINFO, double
precision, dimension( * )WORK, integer, dimension( * )IWORK)
DLA_GERCOND estimates the Skeel condition number for a general matrix.

Purpose:

DLA_GERCOND estimates the Skeel condition number of op(A) * op2(C)
where op2 is determined by CMODE as follows
CMODE =	1    op2(C) = C
CMODE =	0    op2(C) = I
CMODE = -1    op2(C) = inv(C)
The Skeel condition number cond(A) = norminf( |inv(A)||A| )
is computed by computing scaling factors R such that
diag(R)*A*op2(C) is row equilibrated and computing the standard
infinity-norm condition number.

Parameters:
TRANS

TRANS is CHARACTER*1
Specifies the form of the system of equations:
= 'N':  A * X = B	(No transpose)
= 'T':  A**T * X = B	(Transpose)
= 'C':  A**H * X = B	(Conjugate Transpose = Transpose)

N

N is INTEGER
The number of linear equations, i.e., the order of the
matrix A.  N >= 0.

A

A is DOUBLE PRECISION array, dimension (LDA,N)
On entry, the N-by-N matrix A.

LDA

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

AF

AF is DOUBLE PRECISION array, dimension (LDAF,N)
The factors L and U from the factorization
A = P*L*U as computed by DGETRF.

LDAF

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

IPIV

IPIV is INTEGER array, dimension (N)
The pivot indices from the factorization A = P*L*U
as computed by DGETRF; row i of the matrix was interchanged
with row IPIV(i).

CMODE

CMODE is INTEGER
Determines op2(C) in the formula op(A) * op2(C) as follows:
CMODE =  1    op2(C) = C
CMODE =  0    op2(C) = I
CMODE = -1    op2(C) = inv(C)

C

C is DOUBLE PRECISION array, dimension (N)
The vector C in the formula op(A) * op2(C).

INFO

INFO is INTEGER
= 0:	Successful exit.
i > 0:	The ith argument is invalid.

WORK

WORK is DOUBLE PRECISION array, dimension (3*N).
Workspace.

IWORK

IWORK is INTEGER array, dimension (N).
Workspace.

Author:
Univ. of Tennessee

Univ. of California Berkeley