Re: Error in `xcorr` (Signal package) "out of memory or dimension too large for Octave's index type"

[Fabcap77]

Pantxo wrote
> Fabcap77 wrote
>> I need to calculate the autocorrelation coefficients for a vector of 744
>> elements, but `xcorr` fails returning this error message:
>> 
>>    error: out of memory or dimension too large for Octave's index type
>>    error: called from:
>>    error:   /home/$user/octave/signal-1.3.2/xcorr.m at line 203, column 7
>> 
>> The behaviour can be reproduced with:
>> 
>>    var = stdnormal_rnd(744);
>>    [r, lg] = xcorr(var, length(var)/2-1);
>> 
>> Can nybody help to fix this problem?
>> 
>> 
>> 
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> 
> Hi,
> 
> You say you need the autocorrelation coefficients of a vector  of 744
> elements but you are feeding xcorr with a matrix of 744x744 elements. Is
> this intensional? 
> 
> Uhm... I am migrating a script from Scilab, so it is possible that
> something was lost in translation.
> 
> Anyway, I have a vector of 744 values (a time-series) and I want to
> calculate the autocorrelation coefficients for lag = 1 to N-1. That's what
> xcorr is for, right? Or are there better ways?
> 
> 
> If you really want a vector something like "var = stdnormal_rnd (1, 744)"
> would probably do. What you currently do is asking for the
> intercorrelation
> between the autocorrelation vectors of each column of your matrix (see
> "help
> xcorr): 744 (autocorrelation vectors) vecotrs, intercorrelated with each
> other -> 744*744*371 = 205361856 elements for the returned matrix.
> 
> If that is really what you want then you can do it in a loop but it will
> be
> slow.
> 
> Pantxo
> 
> 
> 
> 
> 
> 
> --
> Sent from:
> http://octave.1599824.n4.nabble.com/Octave-General-f1599825.html
> 
> 
> -----------------------------------------
> Join us March 12-15 at CERN near Geneva
> Switzerland for OctConf 2018.  More info:
> https://wiki.octave.org/OctConf_2018
> -----------------------------------------





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