I found the issue https://github.com/sympy/sympy/issues/6835.
Aaron Meurer On Tue, Feb 16, 2016 at 2:39 PM, Aaron Meurer <[email protected]> wrote: > The problem here isn't so much to do with trig identities as the big > numbers. The issue is that things like > factorial(847937526693730893984732849857349) and > 1342**(87236487262873**(8732498237693269832+3)+5)-1) evaluate > automatically, which causes Python to try to compute them until the > memory fills up and it crashes. > > The way I would fix this is to create a special BigInteger object, > which would wrap large integers and avoid explicit computation. For > example, BigInteger(10)**BigInteger(10)**BigInteger(100) would remain > unevaluated. It would then use some algorithms and the assumptions > system to compute facts. So something like > factorial(BigInteger(847937526693730893984732849857349)).is_integer > would be True, which would be enough for > sin(pi*factorial(BigInteger(847937526693730893984732849857349))) to > simplify. There are some cool things that you could do with this, > like (2**BigInteger(74207281) - 1).is_prime. For anyone interested, > there's probably enough cool stuff that could be done here for a GSoC > project. > > (By the way, I had an issue open in the issue tracker a while ago > about this, but I can't find it) > > Aaron Meurer > > On Tue, Feb 16, 2016 at 2:02 PM, Jari-Pekka Ikonen > <[email protected]> wrote: >> Some trigonometric expressions can easily and quickly be simplified without >> ever calculating some of the functions in it just by using the known >> properties of the functions in the expression. >> >> For example: >> >> sin(2*pi) >> >> is 0. So: >> >> sin(pi*factorial(847937526693730893984732849857349)) >> >> is also 0. This does not require calculation of the factorial, but the >> property knowledge, that the result of the factorial is an even integer. >> >> There are several other examples of expressions, like: >> >> tan(pi*(1342^(87236487262873^(8732498237693269832+3)+5)-1)) >> >> is also 0. Several others: >> >> cos(pi*(factorial(8629264243264^64862423642638763847)+1/2)) >> >> is 0. >> >> Could this be implemented in sympy? So many other examples would be much >> faster to calculate. >> >> -- >> 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 https://groups.google.com/group/sympy. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sympy/218ff008-9f3a-479e-8b4e-bca49d646294%40googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. -- 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 https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6Ky9CKCmbA4K%2BTKHUC3338YVCP3J5RtDWQ7qqn8n%2BNayg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
