in reply to Matrix Manipulation with Perl

There are several modules for Matrix math, but most are only useful for lightweight occasional use. Any serious number crunching (where millions of iterations is just getting started) should be done in a native implementation.

The PDL is native code, but I've found it to be a bit immature: a good implementation for some problems, but not as general-purpose as it may first appear.

The good thing about Perl is that you can usually refactor quickly if you have to use some other module instead of the first one you try.

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Re^2: Matrix Manipulation with Perl
by duff (Parson) on Jun 28, 2005 at 04:15 UTC

    Could you elaborate on precisely what you found immature about PDL?

    duff

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Re^2: Matrix Manipulation with Perl
by cdherold (Monk) on Jun 29, 2005 at 06:40 UTC
    So I went and installed Math::Matrix, which does matrices ok, except I could not find a way to do an inverse (which I really really need) even though it said as the header for the documentation it could do inversion, but there was no routine for it.

    So then I decided to try the PDL because it said that it could do inversion and actually had a command called "inv" listed. I got PDL::Matrix and PDL::MatrixOps modules loaded up,

    root@admin PDL-2.4.2# perl -MPDL::Matrix -e shell
    root@admin PDL-2.4.2# perl -MPDL::MatrixOps -e shell
    root@admin PDL-2.4.2#

    but when I tried to run a simple program to confirm it was working I got this error:

    Can't locate object method "xchg" via package "PDL::Matrix" at /usr/lib/perl5/site_perl/5.8.3/i386-linux-thread-multi/PDL/Matrix.pm line 137.

    I am now lost. I do not know what this means except that there might be some module that I need loaded that I forgot to load. Any ideas?

    Chris Herold
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      The above does not "get modules loaded up". It runs two Perl processes each of which load a given module, try to execute the string "shell" (which will evaluate to a string, doing nothing), then exit.

      Instead, the way forward is to run either perldl or pdl2 on the command line, which will load the PDL REPL. It has builtin help, and there is also the MetaCPAN page: https://metacpan.org/pod/perldl.

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      Not that I know anything about PDL at all, but seeing as no one else has responded: can you pare down the simple program to show the error with as few lines as is reasonably possible? That way I could go and install this stuff here and try it out, for example. Or someone else might beat me to it <crossing fingers> ;-)

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