Tuesday, May 30, 2006

PLT Scheme Science Collection

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 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
  • Orginary Differential Equations
  • Chebyshev Approximations
The PLT Scheme Science Collection is available via the PLaneT repository using the following form:

(require (planet "science.ss" ("williams" "science.plt")))

This will download and install the latest version of the science collection. The reference manual is available on the PLT Scheme Help Desk once the collection is installed.
I don't have any updates scheduled for the PLT Scheme Science Collection. Bugs reports or requests for enhancements are welcome, however.

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 and 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-dimensional, continuous distributions (except 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) 1GB of memory failed. This is caused in a bug in the PLT Scheme setup collection that fails on large files. The pdf file for the reference manual -- the large file that caused the problem -- was removed from the distributed science collection.

2-dimensional histogram plots failed. This was an error in the PLoT package distributed with PLT Scheme. It is fixed in V301.5 and later.

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.



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