Re: Missing values

[Schloegl Alois]

Zitiere Marcelo Bruno <address@hidden>:

> Hi everybare,
> i have a matrix with missing values (e.g. 9999 or -9999).
> How does octave work with missing values ???
> Thanks 
> Marcelo Bruno
> Msc. Biological Oceanography student.
> FURG -DEPT.Oceanography - RIO GRANDE - RS - BRAZIL
> 


Often, missing values are encoded with NaN's 
You can change your data with this command
X(X==9999)=nan;
X(X==-9999)=nan;

The default behaviour of Octave is NAN-IN gives NAN-OUT (missing input value
gives missing output value). I implemented an alternative strategie in [1,2] for
various functions. NaN's are handled as missing values. NaN's are basically
skipped. 

I'd suggest this strategy as the default behavior, because it has many
advantages. (see README.TXT at [1]). Are there any objections against
implementing this in Octave?  


Alois 


[1] http://www.dpmi.tu-graz.ac.at/~schloegl/matlab/NaN/
[2] http://www.dpmi.tu-graz.ac.at/~schloegl/matlab/tsa/

 



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