?la_gercond

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

Download PDF

ID 766686

Date 4/28/2026

Version

Public

?la_gercond_x

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

Syntax

call cla_gercond_x ( trans , n , a , lda , af , ldaf , ipiv , x , info , work , rwork )

call zla_gercond_x ( trans , n , a , lda , af , ldaf , ipiv , 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_gercond_x and a DOUBLE COMPLEX vector for zla_gercond_x .

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 A^:code:`T`*X = B (Transpose)

If trans = 'C' , the system has the form A^:code:`H`*X = B (Conjugate Transpose = Transpose)

n

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

a , af , x , work

COMPLEX for cla_gercond_x

DOUBLE COMPLEX for zla_gercond_x

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 .

x , DIMENSION n . The vector x in the formula op(A) * diag(x) .

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) .

rwork

REAL for cla_gercond_x

DOUBLE PRECISION for zla_gercond_x

Array rwork with DIMENSION n is a workspace.

Output Parameters

info

INTEGER .

If info = 0, the execution is successful.
If i > 0, the i -th parameter is invalid.

NOTE:

?getrf

Select Your Language

Using Intel.com Search

Quick Links

Recent Searches

Advanced Search

Only search in