Excellent Burcin - thanks! Ill try your ideas below. Ross On Sat, Apr 24, 2010 at 7:42 PM, Burcin Erocal <bur...@erocal.org> wrote: > On Thu, 22 Apr 2010 20:52:53 -0700 (PDT) > Ross Kyprianou <ros...@gmail.com> wrote: > >> Addendum: I suppose a general query would be how do we incorporate new >> knowledge into Sage (narrowing this down to things like >> >> (a) closed form expressions of integrals > > You should add a new integrator function and register it in the > dictionary sage.symbolic.integration.integral.available_integrators. > > At some point we also need to come up with a protocol to allow these > functions to transform the input and pass it on to be processed by the > next one in the queue. > >> (b) well known expressions of finite or infinite sums > > This is not possible at the moment. We need to setup something like the > framework in sage.symbolic.integration. > >> (c) well known solutions of equations such as the previous message > > This can be done by adding an _eval_() method to > sage.functions.other.Function_erf. It might look like: > > def _eval_(self, x): > if x == 0: > return 0 > return BuiltinFunction._eval_default(self, x) > > Note that checking if a symbolic expression is equal to 0 might be > expensive. Looking at sage/symbolic/expression.pyx, I see that there > is no way to call the is_zero() method of pynac directly from Python. > Perhaps we should allow this, and call this function if the > argument to _eval_ is a symbolic expression. > >> Is it a matter of identifying the area (e.g. pynac, pari, maxima) and >> proposing a change to that codebase (possibly in C or Lisp)? > > All of the above can be done in Python/Cython, if not we should fix > that too. > > > Cheers, > Burcin > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org >
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