def apply_series(self, f, x, x0, n, evaluation):
"""Series[f_, {x_Symbol, x0_, n_Integer}]"""
# TODO:
# - Asymptotic series
# - Series of compositions
vars = {
x.get_name(): x0,
}
data = [f.replace_vars(vars)]
df = f
for i in range(n.get_int_value()):
df = Expression("D", df, x).evaluate(evaluation)
newcoeff = df.replace_vars(vars)
factorial = Expression("Factorial", Integer(i + 1))
newcoeff = Expression(
SymbolTimes,
Expression(SymbolPower, factorial, IntegerMinusOne),
newcoeff,
).evaluate(evaluation)
data.append(newcoeff)
data = Expression(SymbolList, *data).evaluate(evaluation)
return Expression("SeriesData", x, x0, data, IntegerZero, n, Integer1)
