Hi, Are there any modules for vector algebra (three dimensional vectors, vector addition, subtraction, multiplication [scalar and vector]. Could you give me a reference to such module? platform - ubuntu 10.10 (Linux), Python 3.1 or higher. Thanks for your help to avoid re-invention of the wheel. OldAl. -- Algis http://akabaila.pcug.org.au/StructuralAnalysis.pdf