def differentiate_term(term, vars, use_sympy=False):
factors = term.factors
for var in vars:
affected_factors = set(
factor for factor in factors
if var in _factor_symbols(factor, use_sympy=use_sympy))
if not affected_factors:
return Term({Factor('0', eval_method='literal')})
factors = factors.difference(affected_factors).union(
_differentiate_factors(affected_factors, var, use_sympy=use_sympy))
return Term(factors or {Factor('1', eval_method='literal')})
def test_differentiate_term():
t = Term([Factor('a'), Factor('log(b)')])
assert str(differentiate_term(t, ['a'])) == 'log(b)'
assert str(differentiate_term(t, ['log(b)'])) == 'a'
assert str(differentiate_term(t, ['b'])) == '0'
assert str(differentiate_term(t, ['a'], use_sympy=True)) == 'log(b)'
assert str(differentiate_term(t, ['log(b)'], use_sympy=True)) == '0' # 'log(b)' is not in the free symbol list.
assert str(differentiate_term(t, ['b'], use_sympy=True)) == '(1/b):a'
def test_to_terms(self, token_a):
assert token_a.to_terms() == {Term([token_a.to_factor()])}
def term1(self):
return Term([Factor('c'), Factor('b')])
def term2(self):
return Term([Factor('c'), Factor('d')])