# ?la_gercond_c

Computes the infinity norm condition number of op(A)*inv(diag(c)) for general matrices.

## Syntax

FORTRAN 77:

call cla_gercond_c( trans, n, a, lda, af, ldaf, ipiv, c, capply, info, work, rwork )

call zla_gercond_c( trans, n, a, lda, af, ldaf, ipiv, c, capply, info, work, rwork )

## Include Files

• Fortran: mkl.fi
• C: mkl.h

## Description

The function computes the infinity norm condition number of

`op(A) * inv(diag(c))`

where the c is a REAL vector for cla_gercond_c and a DOUBLE PRECISION vector for zla_gercond_c.

## Input Parameters

trans

CHARACTER*1. Must be 'N' or 'T' or 'C'.

Specifies the form of the system of equations:

If `trans = 'N'`, the system has the form A*X = B (No transpose)

If `trans = 'T'`, the system has the form AT*X = B (Transpose)

If `trans = 'C'`, the system has the form AH*X = B (Conjugate Transpose = Transpose)

n

INTEGER. The number of linear equations, that is, the order of the matrix A; n 0.

a, af, work

COMPLEX for cla_gercond_c

DOUBLE COMPLEX for zla_gercond_c

Arrays:

a(lda,*) contains the original general n-by-n matrix A.

af(ldaf,*) contains the factors L and U from the factorization `A=P*L*U` as returned by ?getrf.

work is a workspace array of DIMENSION (2*n).

The second dimension of a and af must be at least `max(1, n)`.

lda

INTEGER. The leading dimension of the array a. lda `max(1,n)`.

ldaf

INTEGER. The leading dimension of af. ldaf `max(1,n)`.

ipiv

INTEGER.

Array with DIMENSION n. The pivot indices from the factorization `A = P*L*U` as computed by ?getrf. Row i of the matrix was interchanged with row `ipiv(i)`.

c, rwork

REAL for cla_gercond_c

DOUBLE PRECISION for zla_gercond_c

Array c with DIMENSION n. The vector c in the formula

`op(A) * inv(diag(c))`.

Array rwork with DIMENSION n is a workspace.

capply

LOGICAL. If capply=.TRUE., then the function uses the vector c from the formula

`op(A) * inv(diag(c))`.

## Output Parameters

info

INTEGER.

If info = 0, the execution is successful.

If i > 0, the i-th parameter is invalid.