It's hard to say for sure without seeing the full traceback. The Mod(1*(2*0) + 1*(1*1), (1*1)*(1*2)) looks like it might be an unevaluated expression. If that's the case, those are known to cause issues because they can break the expectations of various functions.
Aaron Meurer On Wed, Apr 20, 2022 at 2:23 AM Thomas Ligon <[email protected]> wrote: > > I am getting an exception where I don't see why it happens. > > The exception is: > invalid input: Mod(1*(2*0) + 1*(1*1), (1*1)*(1*2)) > > The statement where it is being thrown is: > print(P3().subs(i, 0)) > exp = factor(expand(P3().subs(i, 0))) > > P3() should always return the same thing: > def P3(): > exp = 2*i**2 + 4*i*j + 8*i*m - j**2 +2*m*j + 9*m**2 > return exp > > The print statement is just for debugging purposes. It shows me multiple times > -j**2 + 2*j*m + 9*m**2 > then > 9*m**2 + j*(2*m) - j**2 + (8*0)*m + (4*0)*j + 2*0**2 > invalid input: Mod(1*(2*0) + 1*(1*1), (1*1)*(1*2)) > > So, I can't see why something that should work the same every time suddenly > fails with an exception. The statement P3().subs(i, 0) should always return > the same thing. > > A note on my coding style: P3 could easily be a global constant, but the > function paradigm fits very well with the mathematics that I am reproducing. > The most complex case I have runs recursively, which is very valuable. Also, > I am using "exp" as a local variable that means "expression". > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/c427ce48-8d94-48df-a89c-fea3686b26a3n%40googlegroups.com. -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6Kti3NzOWAW3dcpvD8HDfNoCGrCQdZaSb16H8A6Wf_U4w%40mail.gmail.com.
