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From: Rune Allnor <allnor@tele.ntnu.no>
Newsgroups: comp.soft-sys.matlab
Subject: Re: How to judge a large matrix containing a Nan?
Date: Thu, 1 Jan 2009 02:21:15 -0800 (PST)
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On 1 Jan, 08:12, "zedong  " <zdon...@gmail.com> wrote:
> I now have a sparse matrix which is computed by me(coming from a discretization of partial differential equation,I have used mex file ).
> for example:A is a 10000 by 10000 sparse matrix.
> x=A\b (in which b is a 10000 by 1 matrix).
> I have found that there is some Nan in x.I guess maybe A also has some nan.How to judge that A(i,j) is Nan?Thank you all

ISNAN should tell you whether A contains NaNs. If it does, you would
want to have a look at the mex file which generates A to find out
why they occur.

Rune