Goel, Manisha asked > I need to analyse some substitution matrices, like calculate relative > entropy and matrix subtractions etc. > I was wondering if any simple tool is available for such calculations or > do people always use inhouse mathematics programs to do this ? It probably takes less time to write your own tiny programs in Perl or Python than to find and learn how to use someone else's. If you want a language with good support for matrices, you could try Matlab or even R. ------------------------------------------------------------ Kevin Karplus karplus at soe.ucsc.edu http://www.soe.ucsc.edu/~karplus Professor of Biomolecular Engineering, University of California, Santa Cruz Undergraduate and Graduate Director, Bioinformatics (Senior member, IEEE) (Board of Directors, ISCB) life member (LAB, Adventure Cycling, American Youth Hostels) Effective Cycling Instructor #218-ck (lapsed) Affiliations for identification only.