The same problem as Integral sampling or the same problem as DiracDelta (how is Sum defined for non-integer limits?).
I think in general we should expand out the computation to a symbolic formula and use cse() to make it more efficient (what's the point of being symbolic if we can't do cool tricks like this). Aaron Meurer On Mon, Jul 29, 2013 at 12:35 PM, Stefan Krastanov <[email protected]> wrote: > There is also `Sum(1/x**constant, (x, 1, t))` plotted for t in [1, 10] that > exhibits the same problem. > > > On 29 July 2013 19:33, Stefan Krastanov <[email protected]> wrote: >> >> The fallback is just to call `evalf` instead something like `lambdify`. It >> is always slower, but works even on the most bizarre expressions. For >> integrals, indeed, there are many points that are resampled with this naive >> solution (the algorithm becomes n^2 instead of n). >> >> Numeric libraries like scipy provide routines for doing this in a single >> pass, however one provides the points to be sampled beforehand. mpmath which >> is used in this case does not provide this as far as I know. >> >> Even if it is provided we will have to somehow link this routine to >> `Integral.evalf`, because if we just write a special case for the plotting >> module, it will work for `Integral(...)` but not for something more general >> like `exp(Integral(...))` or `x*Integral(...)`. >> >> So yes, we can implement the single-pass algorithm, but it will require >> some creativity so 1) it will work without us explicitly telling the >> algorithm beforehand which points are to be sampled and 2) it is callable >> like an ordinary `evalf`. > > > -- > 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.
