Hello!
Chapter 6 of the Elementary Algorithms volume by Cohen[1] covers basic
algorithms for manipulation of polynomial expressions. I've added
libraries which implement some of these techiques. Here's a couple of
examples from the unit tests:
(test-equal "EA: Example 6.43"
(collect-terms (alge " 2 a x y + 3 b x y + 4 a x + 5 b x ")
'(x y))
(alge " (2 a + 3 b) x y + (4 a + 5 b) x ")
)
(test-equal "EA: 6.34"
(algebraic-expand (alge " (x+2) * (x+3) * (x+4) "))
(alge " x^3 + 9 x^2 + 26 x + 24 ")
)
As is mentioned in the books, the algorithms presented have some
limitations. Sometimes the exercises cover extensions to overcome these
limitations. Currently, most of the libraries only offer the basic
algorithms without the extensions. In this respect, it's not a bad
foundation for those who want to explore the ideas in the book but don't
have enough time to cook up all the pre-requisite MPL code.
The full unit tests file can be browsed at:
http://github.com/dharmatech/mpl/raw/master/test.sls
All tests pass in Ikarus, Ypsilon, and Mosh.
There's been a slight change in the dependencies. See the README for
details:
http://github.com/dharmatech/mpl/raw/master/README
To check out the repository:
$ git clone git://github.com/dharmatech/mpl.git
Ed
[1] Computer Algebra and Symbolic Computation: Elementary Algorthms
by Joel S. Cohen
