Re: fast hist() / histogram() implementation in C++

[Petr Mikulik]

> > I acknowledge the effort in improving hist.m. Is is as fast as M-language
> > allows. Unfortunately, using it for large images (e.g. 2D detector data)
> > like 512^2 and above goes beyond the user patiency (at least, for me). That
> > was my move to reimplement my own favourite histogram.m into histogram.oct.
> > ...
> > Thus, in average, 50x speedup is achieved for linearly spaced bins,
> > and 27x for logarithmically (or whichever non-linearly) spaced bins.
>
> These improvements do appear to be impressive.
>
> I would recommend that you contribute them to octave-forge,
> probably in the main/general directory.
>
> Additionally, you can ask jwe if he is prepared to add them to
> octave.


I've implemented histogram evaluation in C++: routine histc.cc, and its
corresponding hist.m.

Get it from here:
        http://www.physics.muni.cz/~mikulik/tmp/histc-Nov05.zip

It supports histogram of a vector and 2D matrix.
I don't know how to access dimensions for N-dim matrices. Someone can
contribute the missing code?

Thus I ask -- what do you think -- could this replace hist.m, and contribute
the missing histc function in the Octave package?

Petr



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