Re: handling NaN

[Ben Harris]

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                                          
                                           
                      <address@hidden        To:       address@hidden           
                          
                      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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Octave is freely available under the terms of the GNU GPL.

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