30 lines
1.0 KiB
Python
30 lines
1.0 KiB
Python
from sympy.holonomic.recurrence import RecurrenceOperators, RecurrenceOperator
|
|
from sympy.core.symbol import symbols
|
|
from sympy.polys.domains.rationalfield import QQ
|
|
|
|
def test_RecurrenceOperator():
|
|
n = symbols('n', integer=True)
|
|
R, Sn = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
|
|
assert Sn*n == (n + 1)*Sn
|
|
assert Sn*n**2 == (n**2+1+2*n)*Sn
|
|
assert Sn**2*n**2 == (n**2 + 4*n + 4)*Sn**2
|
|
p = (Sn**3*n**2 + Sn*n)**2
|
|
q = (n**2 + 3*n + 2)*Sn**2 + (2*n**3 + 19*n**2 + 57*n + 52)*Sn**4 + (n**4 + 18*n**3 + \
|
|
117*n**2 + 324*n + 324)*Sn**6
|
|
assert p == q
|
|
|
|
def test_RecurrenceOperatorEqPoly():
|
|
n = symbols('n', integer=True)
|
|
R, Sn = RecurrenceOperators(QQ.old_poly_ring(n), 'Sn')
|
|
rr = RecurrenceOperator([n**2, 0, 0], R)
|
|
rr2 = RecurrenceOperator([n**2, 1, n], R)
|
|
assert not rr == rr2
|
|
|
|
# polynomial comparison issue, see https://github.com/sympy/sympy/pull/15799
|
|
# should work once that is solved
|
|
# d = rr.listofpoly[0]
|
|
# assert rr == d
|
|
|
|
d2 = rr2.listofpoly[0]
|
|
assert not rr2 == d2
|