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Re: PseudoInverse of mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg35865] Re: [mg35844] PseudoInverse of mathematica
  • From: Daniel Lichtblau <danl at wolfram.com>
  • Date: Sun, 4 Aug 2002 06:00:25 -0400 (EDT)
  • References: <200208030416.AAA26681@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Ouafa El Mnafeg wrote:
> 
> Hello,
> When I executed my program in mathematica 4.1, I had a problem with the
> PseudoInverse. The error massage is :
>  "PseudoInverse:: cfail, Algorithm faild to converge"
> Perhaps, the problem is that the matrix is singular. Can you give some
> suggestions to solve this problem? Or is there some function of Mathematica
> useful for this?
> 
> Best regards
> El Mnafeg Ouafa
> Doctorat Student
> Ecole Polythechnique Montreal
> Montreal Canada

It sounds like a failure in the underlying SingularValues computation.
This happens, though rarely, when working with machine arithmetic. You
might try it at higher precision (you can use SetPrecision for this) to
see if it converges then. It will, however, be alot slower.

If your matrix did not have machine numbers then post it or send it and
I can have a closer look.

Daniel Lichtblau
Wolfram Research


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