Maxima Function
factorsum (expr)
Tries to group terms in factors of expr which are sums
into groups of terms such that their sum is factorable. factorsum
can
recover the result of expand ((x + y)^2 + (z + w)^2)
but it can't recover
expand ((x + 1)^2 + (x + y)^2)
because the terms have variables in common.
Example:
(%i1) expand ((x + 1)*((u + v)^2 + a*(w + z)^2)); 2 2 2 2 (%o1) a x z + a z + 2 a w x z + 2 a w z + a w x + v x 2 2 2 2 + 2 u v x + u x + a w + v + 2 u v + u (%i2) factorsum (%); 2 2 (%o2) (x + 1) (a (z + w) + (v + u) )