Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 3/31/2023
Public

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?la_porcond_x

Computes the infinity norm condition number of op(A)*diag(x) for Hermitian positive-definite matrices.

Syntax

call cla_porcond_x( uplo, n, a, lda, af, ldaf, x, info, work, rwork )

call zla_porcond_x( uplo, n, a, lda, af, ldaf, x, info, work, rwork )

Include Files
  • mkl.fi
Description

The function computes the infinity norm condition number of

op(A) * diag(x)

where the x is a COMPLEX vector for cla_porcond_x and a DOUBLE COMPLEX vector for zla_porcond_x.

Input Parameters
uplo

CHARACTER*1. Must be 'U' or 'L'.

Specifies the triangle of A to store:

If uplo = 'U', the upper triangle of A is stored,

If uplo = 'L', the lower triangle of A is stored.

n

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

a

COMPLEX for cla_porcond_c

DOUBLE COMPLEX for zla_porcond_c

Array, DIMENSION(lda, *). On entry, the n-by-n matrix A.

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

lda

INTEGER. The leading dimension of the array a. ldamax(1,n).

af

COMPLEX for cla_porcond_c

DOUBLE COMPLEX for zla_porcond_c

Array, DIMENSION(ldaf, *). The triangular factor L or U from the Cholesky factorization

A = UH*U or A = L*LH,

as computed by ?potrf.

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

ldaf

INTEGER. The leading dimension of the array af. ldafmax(1,n).

x

COMPLEX for cla_porcond_c

DOUBLE COMPLEX for zla_porcond_c

Array x with DIMENSIONn. The vector x in the formula

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

work

COMPLEX for cla_porcond_c

DOUBLE COMPLEX for zla_porcond_c

Array DIMENSION 2*n. Workspace.

rwork

REAL for cla_porcond_c

DOUBLE PRECISION for zla_porcond_c

Array DIMENSIONn. Workspace.

Output Parameters
info

INTEGER.

If info = 0, the execution is successful.

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

See Also