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## Re: handling NaN

 From: Ben Harris Subject: Re: handling NaN Date: Wed, 31 Jul 2002 12:38:00 -0500

```Here is how I would solve this problem--one extra line of code, MATLAB
compatible too:

octave:14> f = [1 2 3 NaN]
f =

1    2    3  NaN

octave:15> idx = find(~isnan(f));
octave:16> max(f(idx))
ans = 3

Regards,
Ben Harris

Heber Farnsworth

wustl.edu>               cc:

Subject:  handling NaN

07/30/2002 04:57

PM

I'm have trouble with NaN values.  I don't mind that they come up
occasionally but I need to know how to get rid of them.  I'm evaluating
a function at various points and I need to pick the maximum point.
Occasionally the point will be an illegal one and it's difficult to
predict when that will happen.  Obviously I don't want that point.
However the following behavior of octave makes it difficult to get the
point I do want.

\$ octave -q
octave:1> f = [1 2 3 NaN]
f =

1    2    3  NaN

octave:2> max(f)
ans = NaN
octave:3> min(f)
ans = NaN
octave:4>

If NaN is both the min and max of any vector it is contained in then how
do I get octave to return the value I want (3 in this case)?

Heber

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