PLT Scheme Science Collection Version 2.2.1 The PLT Scheme Science Collection is a collection of modules that provide functions for numerical computing. The structure of the science collection and many of the underlying algorithms were inspired by the GNU Scientific Library (GSL). The functions are written entirely in PLT Scheme and present a true Scheme look-and-feel throughout. The source code is distributed with the science collection and licensed under the GNU Lesser General Public License (LGPL). The motivation behind the PLT Scheme Science Collection is to provide a numerical framework for knowledge-based simulation in PLT Scheme. Indeed, many of the routines were originally developed as part of the PLT Scheme Simulation Collection. It was noted that that much of the functionality (e.g. random number generation, random distributions, histograms and statistics) did not depend on, or could be separated from, the underlying simulation engine. When this was done, it was further noted that this functionality represented a subset of the functionality in the GSL. At that point, it was decided to use the structure, and to the extent practical, the algorithms of the GSL as a reference model. Thus, the PLT Scheme Science Collection was born. The PLT Scheme Science Collection covers a range of topics in numerical computing. Functions are available for the following areas: * Mathematical Constants and Functions * Special Functions * Random Numbers * Random Distributions * Statistics * Histograms * Ordinary Differential Equations * Chebyshev Approximations The complete reference manual for the PLT Scheme Science Collection is available in HTML format in the PLT Scheme Help Desk. Or, you can contact the author mailto:m.douglas.williams@saic.com for a copy. Version 2.2.1 Version 2.2.1 is a point release of Version 2.2 where the discrete random routines were reimplemented using Walker's O(1) algorithm. Version 2.2 Version 2.2 of the PLT Scheme Science Collection features a reformatted Reference Manual that is compatible with the PLT Scheme Help Desk. The reference manual was written in TeX abd converted to HTML using tex2page. A pdf version of the reference manual is also available. Bug fixes: The gamma-inc-Q function has been added. It was accidentally stubbed out in Version 2.1 Version 2.1 Version 2.1 of the PLT Scheme Science Collection added cummulative density functions for the rest of the 1-deminsional, continuous distributions (except for the Gaussian tail distribution). The corresponding graphics routines were also updated to plot the cummulative density functions. Also, beta, incomplete gamma, and exponential integral special functions were implemented. Bug fixes: The lngamma function returned incorrect values for positive values less than 0.5. Downloading the science collection from PLaneT on a computer with less than (approximately) 1 GB of memory failed. This is caused by a bug in the PLT Scheme setup collection that fails on large fails. The pdf file for the reference manual - the large file that caused the problem - was removed from the distributed science collection. Version 2.0 Version 2.0 of the PLT Scheme Science Collection added ordinary differential equations. These were needed for the PLT Scheme Simulation Collection. Version 1.0 Initial release.