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"""
Tests related to the ``symbol`` attribute of the ABCPolyBase class.
"""
import pytest
import numpy.polynomial as poly
from numpy.core import array
from numpy.testing import assert_equal, assert_raises, assert_
class TestInit:
"""
Test polynomial creation with symbol kwarg.
"""
c = [1, 2, 3]
def test_default_symbol(self):
p = poly.Polynomial(self.c)
assert_equal(p.symbol, 'x')
@pytest.mark.parametrize(('bad_input', 'exception'), (
('', ValueError),
('3', ValueError),
(None, TypeError),
(1, TypeError),
))
def test_symbol_bad_input(self, bad_input, exception):
with pytest.raises(exception):
p = poly.Polynomial(self.c, symbol=bad_input)
@pytest.mark.parametrize('symbol', (
'x',
'x_1',
'A',
'xyz',
'β',
))
def test_valid_symbols(self, symbol):
"""
Values for symbol that should pass input validation.
"""
p = poly.Polynomial(self.c, symbol=symbol)
assert_equal(p.symbol, symbol)
def test_property(self):
"""
'symbol' attribute is read only.
"""
p = poly.Polynomial(self.c, symbol='x')
with pytest.raises(AttributeError):
p.symbol = 'z'
def test_change_symbol(self):
p = poly.Polynomial(self.c, symbol='y')
# Create new polynomial from p with different symbol
pt = poly.Polynomial(p.coef, symbol='t')
assert_equal(pt.symbol, 't')
class TestUnaryOperators:
p = poly.Polynomial([1, 2, 3], symbol='z')
def test_neg(self):
n = -self.p
assert_equal(n.symbol, 'z')
def test_scalarmul(self):
out = self.p * 10
assert_equal(out.symbol, 'z')
def test_rscalarmul(self):
out = 10 * self.p
assert_equal(out.symbol, 'z')
def test_pow(self):
out = self.p ** 3
assert_equal(out.symbol, 'z')
@pytest.mark.parametrize(
'rhs',
(
poly.Polynomial([4, 5, 6], symbol='z'),
array([4, 5, 6]),
),
)
class TestBinaryOperatorsSameSymbol:
"""
Ensure symbol is preserved for numeric operations on polynomials with
the same symbol
"""
p = poly.Polynomial([1, 2, 3], symbol='z')
def test_add(self, rhs):
out = self.p + rhs
assert_equal(out.symbol, 'z')
def test_sub(self, rhs):
out = self.p - rhs
assert_equal(out.symbol, 'z')
def test_polymul(self, rhs):
out = self.p * rhs
assert_equal(out.symbol, 'z')
def test_divmod(self, rhs):
for out in divmod(self.p, rhs):
assert_equal(out.symbol, 'z')
def test_radd(self, rhs):
out = rhs + self.p
assert_equal(out.symbol, 'z')
def test_rsub(self, rhs):
out = rhs - self.p
assert_equal(out.symbol, 'z')
def test_rmul(self, rhs):
out = rhs * self.p
assert_equal(out.symbol, 'z')
def test_rdivmod(self, rhs):
for out in divmod(rhs, self.p):
assert_equal(out.symbol, 'z')
class TestBinaryOperatorsDifferentSymbol:
p = poly.Polynomial([1, 2, 3], symbol='x')
other = poly.Polynomial([4, 5, 6], symbol='y')
ops = (p.__add__, p.__sub__, p.__mul__, p.__floordiv__, p.__mod__)
@pytest.mark.parametrize('f', ops)
def test_binops_fails(self, f):
assert_raises(ValueError, f, self.other)
class TestEquality:
p = poly.Polynomial([1, 2, 3], symbol='x')
def test_eq(self):
other = poly.Polynomial([1, 2, 3], symbol='x')
assert_(self.p == other)
def test_neq(self):
other = poly.Polynomial([1, 2, 3], symbol='y')
assert_(not self.p == other)
class TestExtraMethods:
"""
Test other methods for manipulating/creating polynomial objects.
"""
p = poly.Polynomial([1, 2, 3, 0], symbol='z')
def test_copy(self):
other = self.p.copy()
assert_equal(other.symbol, 'z')
def test_trim(self):
other = self.p.trim()
assert_equal(other.symbol, 'z')
def test_truncate(self):
other = self.p.truncate(2)
assert_equal(other.symbol, 'z')
@pytest.mark.parametrize('kwarg', (
{'domain': [-10, 10]},
{'window': [-10, 10]},
{'kind': poly.Chebyshev},
))
def test_convert(self, kwarg):
other = self.p.convert(**kwarg)
assert_equal(other.symbol, 'z')
def test_integ(self):
other = self.p.integ()
assert_equal(other.symbol, 'z')
def test_deriv(self):
other = self.p.deriv()
assert_equal(other.symbol, 'z')
def test_composition():
p = poly.Polynomial([3, 2, 1], symbol="t")
q = poly.Polynomial([5, 1, 0, -1], symbol="λ_1")
r = p(q)
assert r.symbol == "λ_1"
#
# Class methods that result in new polynomial class instances
#
def test_fit():
x, y = (range(10),)*2
p = poly.Polynomial.fit(x, y, deg=1, symbol='z')
assert_equal(p.symbol, 'z')
def test_froomroots():
roots = [-2, 2]
p = poly.Polynomial.fromroots(roots, symbol='z')
assert_equal(p.symbol, 'z')
def test_identity():
p = poly.Polynomial.identity(domain=[-1, 1], window=[5, 20], symbol='z')
assert_equal(p.symbol, 'z')
def test_basis():
p = poly.Polynomial.basis(3, symbol='z')
assert_equal(p.symbol, 'z')
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