On Tue, Oct 22, 2013 at 11:59 AM, F. B. <[email protected]> wrote: > > Other considerations: is SymPy able to match subtrees in the args tree? What > I have understood from the docstrings, is that the matcher tries to match > the whole expression tree, not a part of it. > > The tensor module is somewhat anomalous, because the way you write tensors > is not the same as the expression tree, which contains additional > information. I should be interesting to have a look at xAct into detail, I > suppose they use something similar to assumptions or tools by Mathematica. I > have not a very good knowledge of Mathematica language, though. > > In any case, subtree pattern matching could be an interesting matter, that's > more graph-like than tree-like. > > I'm still convinced that the tensor module needs its own pattern matcher, > the other way would be to relocate arg-tree internal data to the > assumptions, or to some other global variable.
If you want to use a lot of mathematical knowledge about tensor expressions that is not true for expressions in general, then a custom pattern matcher will probably be more efficient and easier to write than a generic one. Aaron Meurer > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. For more options, visit https://groups.google.com/groups/opt_out.
