I've asked about factoring before but am just jotting down some observations that I've made in the last few days. I was talking with Aaron the other day about a routine and suggested he should use factoring. He says, "that's gong to be expensive." I got to thinking.
There are really 3 (at least) types of factoring: 1) factoring that can be done by inspection of factors. I call this separation. Pursued recursively, it leads to a possible separation of variables: x + x*y + a + a*y x*(1 + y) + a*(1 + y) (x+a)*(1+y) This should be very fast factoring since you are looking for existing factors, not extractable factors. separatevars should be re-written to not use factor since that expensive operation is not needed for this. 2) factoring that can be done be extraction of common bases: x + x**2 x*(1 + x) This should be pretty fast since you have the factor candidates already visible but you need to see if they can be extracted from other bases. This sort of factoring is available through terms_gcd 3) factoring that can be done only by identifying potential factors and doing trial division. x**2 - 1 (x+1)*(x-1) This is available through factor, but perhaps factor should try the other simpler methods before resorting to level 3 factoring. -- You received this message because you are subscribed to the Google Groups "sympy-patches" group. To post to this group, send email to sympy-patc...@googlegroups.com. To unsubscribe from this group, send email to sympy-patches+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy-patches?hl=en.
