Campus Livre
isIllConditioned
Tests whether a decomposition object represents an ill-conditioned matrix.
Category: Mathematics > Linear Algebra
Syntax
tf = isIllConditioned(dA)True if the matrix factored in the decomposition object dA is ill conditioned.
Description
A solution computed from an ill-conditioned matrix may have lost most of its accuracy. The test compares the reciprocal condition number of the matrix with a threshold related to machine precision, using the factorization already stored in the object, so no new factorization is needed.
The function applies to decomposition objects only, not to plain matrices; for those, use rcond or cond.
Input arguments
dA- A
decompositionobject.
Output arguments
tf- Logical scalar.
Example
A well-conditioned matrix
dA = decomposition([4 1; 2 3]);
isIllConditioned(dA)
rcond(dA)Output
ans = logical
0
ans = 0.3333