def test_series_of_Subs():
from sympy.abc import x, y, z
subs1 = Subs(sin(x), x, y)
subs2 = Subs(sin(x) * cos(z), x, y)
subs3 = Subs(sin(x * z), (x, z), (y, x))
assert subs1.series(x) == subs1
subs1_series = (
Subs(x, x, y) + Subs(-(x ** 3) / 6, x, y) + Subs(x ** 5 / 120, x, y) + O(y ** 6)
)
assert subs1.series() == subs1_series
assert subs1.series(y) == subs1_series
assert subs1.series(z) == subs1
assert subs2.series(z) == (
Subs(z ** 4 * sin(x) / 24, x, y)
+ Subs(-(z ** 2) * sin(x) / 2, x, y)
+ Subs(sin(x), x, y)
+ O(z ** 6)
)
assert subs3.series(x).doit() == subs3.doit().series(x)
assert subs3.series(z).doit() == sin(x * y)
raises(ValueError, lambda: Subs(x + 2 * y, y, z).series())
assert Subs(x + y, y, z).series(x).doit() == x + z
def test_series_of_Subs():
from sympy.abc import x, y, z
subs1 = Subs(sin(x), x, y)
subs2 = Subs(sin(x) * cos(z), x, y)
subs3 = Subs(sin(x * z), (x, z), (y, x))
assert subs1.series(x) == subs1
assert subs1.series(y) == Subs(x, x, y) + Subs(-x**3/6, x, y) + Subs(x**5/120, x, y) + O(y**6)
assert subs1.series(z) == subs1
assert subs2.series(z) == Subs(z**4*sin(x)/24, x, y) + Subs(-z**2*sin(x)/2, x, y) + Subs(sin(x), x, y) + O(z**6)
assert subs3.series(x).doit() == subs3.doit().series(x)
assert subs3.series(z).doit() == sin(x*y)
def test_series_of_Subs():
from sympy.abc import x, y, z
subs1 = Subs(sin(x), x, y)
subs2 = Subs(sin(x) * cos(z), x, y)
subs3 = Subs(sin(x * z), (x, z), (y, x))
assert subs1.series(x) == subs1
assert subs1.series(y) == Subs(x, x, y) + Subs(-x**3 / 6, x, y) + Subs(
x**5 / 120, x, y) + O(y**6)
assert subs1.series(z) == subs1
assert subs2.series(z) == Subs(z**4 * sin(x) / 24, x, y) + Subs(
-z**2 * sin(x) / 2, x, y) + Subs(sin(x), x, y) + O(z**6)
assert subs3.series(x).doit() == subs3.doit().series(x)
assert subs3.series(z).doit() == sin(x * y)
def test_series_of_Subs():
from sympy.abc import x, y, z
subs1 = Subs(sin(x), x, y)
subs2 = Subs(sin(x) * cos(z), x, y)
subs3 = Subs(sin(x * z), (x, z), (y, x))
assert subs1.series(x) == subs1
subs1_series = (Subs(x, x, y) + Subs(-x**3/6, x, y) +
Subs(x**5/120, x, y) + O(y**6))
assert subs1.series() == subs1_series
assert subs1.series(y) == subs1_series
assert subs1.series(z) == subs1
assert subs2.series(z) == (Subs(z**4*sin(x)/24, x, y) +
Subs(-z**2*sin(x)/2, x, y) + Subs(sin(x), x, y) + O(z**6))
assert subs3.series(x).doit() == subs3.doit().series(x)
assert subs3.series(z).doit() == sin(x*y)
raises(ValueError, lambda: Subs(x + 2*y, y, z).series())
assert Subs(x + y, y, z).series(x).doit() == x + z