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MathGroup Archive 1998

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ANNOUNCE: Math::ematica 1.100 - Perl talks to Mathematica


  • To: mathgroup@smc.vnet.net
  • Subject: [mg10281] ANNOUNCE: Math::ematica 1.100 - Perl talks to Mathematica
  • From: Ulrich Pfeifer <pfeifer@wait.de>
  • Date: Sat, 3 Jan 1998 23:24:13 -0500
  • Organization: University of Dortmund, Germany

"Happy new year, Miss Sophie!"

After nearly a year Math::ematica, a Perl Interface to the MathLink
library of Mathematica, is back. It's rewritten from scratch (So if you
did not like the old module, give it another try ;-). I consider this
alpha software because the interface might be different in upcoming
releases. Appart from that, the module should be quite usable (see the
README below). I'd be happy about any feedback you care to provide.
Tell me what is needed to make the module (even more ;-) useful to you.

Math-ematica-1.100.tar.gz should already be propagated through the
Comprehensive Perl Archive Network (CPAN). Get it from:

  http://www.perl.com/CPAN/authors/id/ULPFR/Math-ematica-1.100.tar.gz

"I now declare this bazar opened!"

Ulrich Pfeifer
--
NAME
    Math::ematica - Perl extension for connecting Mathematica(TM)

SYNOPSIS
      use Math::ematica qw(:PACKET :TYPE :FUNC);

WARNING
    This is alpha software. User visible changes can happen any
    time.

    The module is completely rewritten. Literally no line of the old
    stuff is used (don't ask - I've learned a few things since these
    days ;-). If you are using the old 1.006 version, note that the
    interface has changed. If there is an overwhelming outcry, I
    will provide some backward compatibility stuff.

    Feel free to suggest modifications and/or extensions. I do not
    use Mathematica for real work right now and may fail to foresee
    the most urgent needs. Even if you think that the interface is
    great, you are invited to complete the documentation (and fix
    grammos and typos). Since I am no native English speaker, I will
    delay the writing of real documentation until the API has
    stabilized.

    I do develop this module using Mathematica 3.0.1 on a Linux
    2.0.30 box. Let me know, if it does work with other versions of
    Mathematica or does not work on other *nix flavors.

DESCRIPTION
    The `Math::ematica' module provides an interface to the
    MathLink(TM) library. Functions are not exported and should be
    called as methods. Therefore the Perl names have the 'ML' prefix
    stripped. Since Perl can handle multiple return values, methods
    fetching elements from the link return the values instead of
    passing results in reference parameters.

    The representation of the data passed between Perl and
    Mathematica is straight forward exept the symbols which are
    represented as blessed scalars in Perl.

Exported constants
    `PACKET'
         The `PACKET' tag identifies constants used as packet types.

           print "Got result packet" if $link->NextPacket == RETURNPKT;

    `TYPE'
         The `TYPE' tag identifies constants used as elements types.

           print "Got a symbol" if $link->GetNext == MLTKSYM;

Exported functions
    `FUNC'
         The `FUNC' tag currently only contains the `symbol'
         function which returns the symbol for a given name.

           $sym = symbol 'Sin';

The plain interface
    This set of methods gives you direct access to the MathLink
    function. Don't despair if you don't know them too much. There
    is a convenient layer ontop of them ;-). Methods below are only
    commented if they do behave different than the corresponding C
    functions. Look in your MathLink manual for details.

  `new'

    The constructor is just a wrapper around `MLOpenArgv'.

      $link = new Math::ematica '-linklaunch', '-linkname', 'math
-mathlink';

    The link is automatically activated on creation and will be
    closed upon destruction.

  `ErrorMessage'

      print $link->ErrorMessage;

  `EndPacket'

  `Flush'

  `NewPacket'

  `NextPacket'

  `Ready'

  `PutSymbol'

  `PutString'

  `PutInteger'

  `PutDouble'

  `PutFunction'

  `GetNext'

  `GetInteger'

  `GetDouble'

  `GetString'

    The method does the appropriate `MLDisownString' call for you.

  `GetSymbol'

    The module does the appropriate `MLDisownSymbol' call for you.
    It also blesses the result string into the package
    `Math::ematica::symbol'.

  `Function'

    Returns the function name and argument count in list context. In
    scalar contex only the function name is returned.

  `GetRealList'

    Returns the array of reals.

The convenience interface
  `PutToken'

    Puts a single token according to the passed data type.

      $link->PutToken(1);               # MLPutInteger

    Symbols are translated to `MLPutFunction' if the arity is
    provided as aditional parameter.

      $link->PutToken(symbol 'Pi');     # MLPutSymbol
      $link->PutToken(symbol 'Sin', 1); # MLPutFunction

  `read_packet'

    Reads the current packet and returns it as nested data
    structure. The implementaion is not complete. But any packet
    made up of `MLTKREAL', `MLTKINT', `MLTKSTR', `MLTKSYM', and
    `MLTKFUNC' should translate correctely. A function symbol `List'
    is dropped automatically. So the Mathematica expression
    `List[1,2,3]' translates to the Perl expression `[1,2,3]'.

    *Mabybe this is *too* convenient?*.

  `call'

    Call is the main convenience interface. You will be able to do
    most if not all using this call.

    Note that the syntax is nearly the same as you are used to as
    *FullForm* in Mathematica. Only the function names are moved
    inside the brackets and separated with ',' from the arguments.
    The method returns the nested data structures read by
    `read_packet'.

      $link->call([symbol 'Sin', 3.14159265358979/2]); # returns
something near 1

    To get a table of values use:

      $link->call([symbol 'Table',
                   [symbol 'Sin', symbol 'x'],
                   [symbol 'List', symbol 'x',  0, 1, 0.1]]);

    This returns a reference to an array of doubles.

    You may omit the first `symbol'. *Maybe we should choose the
    default mapping to *Symbol* and require *Strings*s to be marked?*

  `install'

    If you find this too ugly, you may `install' Mathematica
    functions as Perl functions using the `install' method.

      $link->install('Sin',1);
      $link->install('Pi');
      $link->install('N',1);
      $link->install('Divide',2);

      Sin(Divide(Pi(),2.0)) # should return 1 (on machines which can
                            # represent '2.0' *exactely* in a double ;-)

    The `install' method takes the name of the Mathematica function,
    the number of arguments and optional the name of the Perl
    function as argument.

      $link->install('Sin',1,'sin_by_mathematica');

    Make shure that you do not call any *installed* function after
    the `$link' has gone. Wild things will happen!

  `send_packet'

    Is the sending part of `call'. It translates the expressions
    passed to a Mathematica package and puts it on the link.

  `register'

    This method allows to register your Perl functions to
    Mathematica. *Registered* functions may be called during
    calculations.

      sub addtwo {
        $_[0]+$_[1];
      }

      $link->register('AddTwo', \&addtwo, 'Integer', 'Integer');
      $link->call([symbol 'AddTwo',12, 3]) # returns 15

    You may register functions with unspecified argument types using
    undef:

      sub do_print {
        print @_;
      }
      $link->register('DoPrint', undef);
      $link->call(['DoPrint',12]);
      $link->call(['DoPrint',"Hello"]);

AUTHOR
    Ulrich Pfeifer <pfeifer@wait.de>

SEE ALSO
    See also the perl(1) manpage and your Mathematica and MathLink
    documentation. Also check the t/*.t files in the distribution.

ACKNOWLEDGEMENTS
    I wish to thank Jon Orwant of *The Perl Journal*, Nancy Blachman
    from *The Mathematica Journal*, and Brett H. Barnhart from
    *Wolfram Research*.

    Jon brought the earlier versions of this module to the attention
    of Nancy Blachman. She in turn did contact Brett H. Barnhart who
    was so kind to provide a trial license which made this work
    possible.

    So subscribe to *The Perl Journal* and *The Mathematica Journal*
    if you are not subscribed already if you use this module (a
    Mathematica license is needed anyway). You would be nice to nice
    people and may even read something more about this module one
    day ;-)

Copyright
    The Math:ematica module is Copyright (c) 1996,1997 Ulrich
    Pfeifer. Germany. All rights reserved.

    You may distribute under the terms of either the GNU General
    Public License or the Artistic License, as specified in the Perl
    README file.

    Mathematica and MathLink are registered trademarks of Wolfram
    Research.




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