MAXIMA as a Server

Coupling LON-CAPA with MAXIMA was a challenge, since MAXIMA was originally designed to be run interactively, so, unfortunately, the command line option "-s port" of MAXIMA does not establish a server port to which you can connect. For scalablity reasons, though, it is prohibitive to start a new MAXIMA process for every evaluation of an expression.

We also had problems with different LISP versions - the one we used is

Maxima 5.9.2.99rc1 http://maxima.sourceforge.net
Using Lisp SBCL 0.9.10

i.e, the Steel Bank Common Lisp.

The following code might be helpful as a starting point for other projects in which you would like to connect to running MAXIMA processes - of course you would need to remove the LON-CAPAisms:

• Server script lonmaxima - this server script generates a configurable number of server processes that listen to a UNIX socket. Each of these processes is connected to a running MAXIMA process.

  [www@phy1 Apache]$ ps aux |grep maxima
  www      14721  0.0  0.5  9420 5460 ?        S    11:14   0:00 lonmaxima: Parent process, sleeping Sat Mar 11 11:14:41 2006
  www      14722  0.0  0.5  9420 5508 ?        S    11:14   0:00 lonmaxima: Accepting connections Sat Mar 11 11:23:09 2006
  www      14723  0.0  2.2 885900 23348 pts/1  S    11:14   0:00 sbcl --core /usr/local/lib/maxima/5.9.2.99rc1/binary-sbcl/maxima.core --noinform --end-runtime-options --eval (cl-user::run) --end-toplevel-options
  www      14724  0.0  0.5  9420 5508 ?        S    11:14   0:00 lonmaxima: Accepting connections Sat Mar 11 11:19:59 2006
  www      14725  0.0  0.5  9420 5508 ?        S    11:14   0:00 lonmaxima: Accepting connections Sat Mar 11 11:23:51 2006
  www      14726  0.0  2.2 885900 23204 pts/4  S    11:14   0:00 sbcl --core /usr/local/lib/maxima/5.9.2.99rc1/binary-sbcl/maxima.core --noinform --end-runtime-options --eval (cl-user::run) --end-toplevel-options
  www      14727  0.0  0.5  9420 5508 ?        S    11:14   0:00 lonmaxima: Accepting connections Sat Mar 11 11:22:35 2006
  www      14736  0.0  2.2 885900 23304 pts/5  S    11:14   0:00 sbcl --core /usr/local/lib/maxima/5.9.2.99rc1/binary-sbcl/maxima.core --noinform --end-runtime-options --eval (cl-user::run) --end-toplevel-options
  www      14739  0.0  0.5  9420 5508 ?        S    11:14   0:00 lonmaxima: Accepting connections Sat Mar 11 11:24:57 2006
  www      14742  0.0  2.2 885900 23304 pts/6  S    11:14   0:00 sbcl --core /usr/local/lib/maxima/5.9.2.99rc1/binary-sbcl/maxima.core --noinform --end-runtime-options --eval (cl-user::run) --end-toplevel-options
  www      14775  0.0  2.2 885900 23112 pts/7  S    11:14   0:00 sbcl --core /usr/local/lib/maxima/5.9.2.99rc1/binary-sbcl/maxima.core --noinform --end-runtime-options --eval (cl-user::run) --end-toplevel-options
  www      15172  0.0  0.0  5620  612 pts/8    S    11:52   0:00 grep maxima
  [www@phy1 Apache]$
  

• Client library lonmaxima.pm - some small routines to connect to the MAXIMA server. Example:
  

              use Apache::lonmaxima();
  ...
  
      my $socket=&Apache::lonmaxima::connect();
      $r->print(
                &Apache::lonmaxima::compareterms($socket,'a*x**2','x*a*x')."<br />".
                &Apache::lonmaxima::compareterms($socket,'sin(x)**2','cos(x)**2')."<br />".
                &Apache::lonmaxima::compareterms($socket,'sin(x)**2+cos(x)**2','1')."<br />"
                );
      &Apache::lonmaxima::disconnect($socket);
  
  

  - gives you

  true
  false
  true