clean - cleans matrices (round to zero small entries)

Calling Sequence

[B]=clean(A [,epsa [,epsr]])

Parameters

• A : a numerical matrix (scalar, polynomial, sparse...)
• epsa,epsr : real numbers (default values resp. 1.d-10 and 1.d-10)

Description

This function eliminates (i.e. set to zero) all the coefficients with absolute value < epsa and relative value < epsr (relative means relative w.r.t. 1-norm of coefficients) in a polynomial (possibly matrix polynomial or rational matrix).

Default values are epsa=1.d-10 and epsr=1.d-10;

For a constant (non polynomial) matrix clean(A,epsa) sets to zero all entries of A smaller than epsa.

Examples

x=poly(0,'x');
w=[x,1,2+x;3+x,2-x,x^2;1,2,3+x]/3;
w*inv(w)
clean(w*inv(w))