.Modelica.Math.Matrices.rcond

Information

Syntax

r = Matrices.rcond(A);

Description

This function estimates the reciprocal of the condition number (norm(A) * norm(inv(A))) of a general real matrix A, in either the 1-norm or the infinity-norm, using the LAPACK function DGECON. If rcond(A) is near 1.0, A is well conditioned and A is ill conditioned if rcond(A) is near zero.

Example

A = [1, 2;
     2, 1];
r = rcond(A);

results in:

r = 0.3333

See also

Matrices.conditionNumber

Interface

function rcond
  extends Modelica.Icons.Function;
  input Real A[:, size(A, 1)] "Square real matrix";
  input Boolean inf = false "Is true if infinity norm is used and false for 1-norm";
  output Real rcond "Reciprocal condition number of A";
  output Integer info "Information";
end rcond;

Revisions

• 2010/05/31 by Marcus Baur, DLR-RM