Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 11/07/2023
Public

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?la_gercond_c

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

Syntax

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

  • mkl.fi

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 DIMENSIONn. 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 DIMENSIONn. The vector c in the formula

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

Array rwork with DIMENSIONn 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.

See Also