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suppress condition warning on inv?


From: Paul Kienzle
Subject: suppress condition warning on inv?
Date: Thu, 22 Mar 2001 00:32:43 +0000
User-agent: Mutt/1.2.5i

Hi!  I'm working with some potentially ill-conditioned matrices
Which when I invert them may give a warning message:

warning: inverse: matrix singular to machine precision, rcond = 1.34804e-30

Is there a way to return rcond, or suppress the warning, or know
quickly ahead of time if the warning will be issued?  

I already have the schur decomposition and the eigenvalues/eigenvectors
of the matrix if that helps.  

Calling cond/svd takes 2x longer than the inverse itself, and if it
passes, I will still want to do the inverse, so that's not an ideal solution.

Shall I patch inv.cc so that it accepts the form: [X, rcond] = inv(A); ?

        ...

        retval(0) = m.inverse (info, rcond, 1);

        if (nargout > 1)
          retval(1) = rcond;
        else if (info == -1)
          warning ("inverse: matrix singular ...", rcond);

        ...

Paul Kienzle
address@hidden



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