Ruby library for scientific graphs

 Tioga is a blend of PDF, pdfTex and ruby into a library to make
 scientific graphs of high quality. It is fairly complete and
 extensive, and comes with examples and (online) complete documentation.
 .
 Tioga is useful for scripting the generation of graphs, and comes
 with a configuration file for irb for interactive plotting of pictures.
 .
 A PDF viewer is strongly recommended if you want to make use of the
 tioga script, a wrapper around some of the library functionalities.