def common_terms(pair):
# print "common_terms: finding common terms of " + str(pair)
if Rule.all_are(pair, Const):
return const_common_terms(pair)
if Rule.all_are(pair, Var):
if pair[0] == pair[1]:
return [pair[0]]
else:
return []
if Rule.all_are(pair, Atom):
return []
if Rule.all_are(pair, Multiply):
return mult_common_terms(pair)
if Rule.is_a(pair[0], Multiply) and Rule.is_a(pair[1], Atom):
return mult_atom_common_terms(pair)
if Rule.is_a(pair[0], Atom) and Rule.is_a(pair[1], Multiply):
return mult_atom_common_terms((pair[1], pair[0]))
if Rule.all_are(pair, Power):
return pow_common_terms(pair)
if Rule.is_a(pair[0], Power) and Rule.is_a(pair[1], Atom):
return pow_atom_common_terms(pair)
if Rule.is_a(pair[0], Atom) and Rule.is_a(pair[1], Power):
return pow_atom_common_terms((pair[1], pair[0]))
if Rule.is_a(pair[0], Multiply) and Rule.is_a(pair[1], Power):
return mult_pow_common_terms(pair)
if Rule.is_a(pair[0], Power) and Rule.is_a(pair[1], Multiply):
return mult_pow_common_terms((pair[1], pair[0]))
return []
def pow_common_terms(pair):
# print "pow_common_terms: finding common terms of " + str(pair)
if not Rule.all_equal([term.base() for term in pair]):
return []
if Rule.all_are([term.exponent() for term in pair], Var):
return []
if Rule.all_are([term.exponent() for term in pair], Const):
if Rule.all_are([term.exponent().value() for term in pair], int):
v1 = pair[0].exponent().value()
v2 = pair[1].exponent().value()
return [Power(pair[0].base(), Const(min(v1, v2)))]
common_in_exp = common_terms((pair[0].exponent(), pair[1].exponent()))
if len(common_in_exp) > 0:
if len(common_in_exp) > 1:
mults = Multiply(*common_in_exp)
else:
mults = common_in_exp[0]
return [Power(pair[0].base(), mults)]
return []
