>From what little I know of Set theory , I seem to remember that, U(1..n)Ai = Sum(|Ai|)-Sum(|Ai^Aj|)+Sum(|Ai^Aj^Ak|).... totally 2**n-1 terms.
I guess it should be possible to write something to do this. I'll see if I can come up with something. Akshay On Jan 19, 7:19 am, Reckoner <[email protected]> wrote: > Thanks. > > I am computing something like > > Prob(A + B) = Prob(A) + Prob(B) - Prob(A*B) > > for a complicated discrete distribution where '+' means union and '*' > means intersection. This is simple enough for a small number of sets, > but there might be millions of sets and the above formula gets more > complex since the sets are not disjoint. > > For instance, > > Prob(A + B + B) = Prob(A) + Prob(B)+ Prob(C) - Prob(A*B) - Prob(A*C) - > Prob(B*C) + Prob(A*B*C) > > The Prob(A*B*C) terms are themselves complicated to generate. > > Any ideas? > > On Jan 18, 8:39 am, "Ondrej Certik" <[email protected]> wrote: > > > Hi Reckoner, > > > On Sat, Jan 17, 2009 at 12:51 PM, Reckoner <[email protected]> wrote: > > > > I know python has a set() object, but I'm wondering if sympy has set > > > algebra built into it (e.g. union, intersection) for symbolic objects. > > > Note that I'm interested in manipulating the sets themselves and not > > > necessarily what's in those sets. > > > > I hope that made some sense. > > > As far as I know, you can only use python set() so far (it works well > > with sympy though). Do you have some examples what you'd like to do > > symbolically? Maybe it's easy to implement. > > > Ondrej > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sympy?hl=en -~----------~----~----~----~------~----~------~--~---
