def test_issue_14291():
assert Poly(((x - 1)**2 + 1)*((x - 1)**2 + 2)*(x - 1)
).all_roots() == [1, 1 - I, 1 + I, 1 - sqrt(2)*I, 1 + sqrt(2)*I]
p = x**4 + 10*x**2 + 1
ans = [rootof(p, i) for i in range(4)]
assert Poly(p).all_roots() == ans
_check(ans)
def test_issue_8285():
roots = (Poly(4*x**8 - 1, x)*Poly(x**2 + 1)).all_roots()
assert roots == _nsort(roots)
f = Poly(x**4 + 5*x**2 + 6, x)
ro = [rootof(f, i) for i in range(4)]
roots = Poly(x**4 + 5*x**2 + 6, x).all_roots()
assert roots == ro
assert roots == _nsort(roots)
# more than 2 complex roots from which to identify the
# imaginary ones
roots = Poly(2*x**8 - 1).all_roots()
assert roots == _nsort(roots)
assert len(Poly(2*x**10 - 1).all_roots()) == 10 # doesn't fail
def test_CRootOf():
assert str(rootof(x**5 + 2*x - 1, 0)) == "CRootOf(x**5 + 2*x - 1, 0)"
def test_CRootOf():
assert str(rootof(x**5 + 2 * x - 1, 0)) == "CRootOf(x**5 + 2*x - 1, 0)"
def _get_euler_characteristic_eq_sols(eq, func, match_obj):
r"""
Returns the solution of homogeneous part of the linear euler ODE and
the list of roots of characteristic equation.
The parameter ``match_obj`` is a dict of order:coeff terms, where order is the order
of the derivative on each term, and coeff is the coefficient of that derivative.
"""
x = func.args[0]
f = func.func
# First, set up characteristic equation.
chareq, symbol = S.Zero, Dummy('x')
for i in match_obj:
if i >= 0:
chareq += (match_obj[i] * diff(x**symbol, x, i) *
x**-symbol).expand()
chareq = Poly(chareq, symbol)
chareqroots = [rootof(chareq, k) for k in range(chareq.degree())]
collectterms = []
# A generator of constants
constants = list(get_numbered_constants(eq, num=chareq.degree() * 2))
constants.reverse()
# Create a dict root: multiplicity or charroots
charroots = defaultdict(int)
for root in chareqroots:
charroots[root] += 1
gsol = S.Zero
ln = log
for root, multiplicity in charroots.items():
for i in range(multiplicity):
if isinstance(root, RootOf):
gsol += (x**root) * constants.pop()
if multiplicity != 1:
raise ValueError("Value should be 1")
collectterms = [(0, root, 0)] + collectterms
elif root.is_real:
gsol += ln(x)**i * (x**root) * constants.pop()
collectterms = [(i, root, 0)] + collectterms
else:
reroot = re(root)
imroot = im(root)
gsol += ln(x)**i * (
x**reroot) * (constants.pop() * sin(abs(imroot) * ln(x)) +
constants.pop() * cos(imroot * ln(x)))
collectterms = [(i, reroot, imroot)] + collectterms
gsol = Eq(f(x), gsol)
gensols = []
# Keep track of when to use sin or cos for nonzero imroot
for i, reroot, imroot in collectterms:
if imroot == 0:
gensols.append(ln(x)**i * x**reroot)
else:
sin_form = ln(x)**i * x**reroot * sin(abs(imroot) * ln(x))
if sin_form in gensols:
cos_form = ln(x)**i * x**reroot * cos(imroot * ln(x))
gensols.append(cos_form)
else:
gensols.append(sin_form)
return gsol, gensols
def _get_const_characteristic_eq_sols(r, func, order):
r"""
Returns the roots of characteristic equation of constant coefficient
linear ODE and list of collectterms which is later on used by simplification
to use collect on solution.
The parameter `r` is a dict of order:coeff terms, where order is the order of the
derivative on each term, and coeff is the coefficient of that derivative.
"""
x = func.args[0]
# First, set up characteristic equation.
chareq, symbol = S.Zero, Dummy('x')
for i in r.keys():
if type(i) == str or i < 0:
pass
else:
chareq += r[i] * symbol**i
chareq = Poly(chareq, symbol)
# Can't just call roots because it doesn't return rootof for unsolveable
# polynomials.
chareqroots = roots(chareq, multiple=True)
if len(chareqroots) != order:
chareqroots = [rootof(chareq, k) for k in range(chareq.degree())]
chareq_is_complex = not all(i.is_real for i in chareq.all_coeffs())
# Create a dict root: multiplicity or charroots
charroots = defaultdict(int)
for root in chareqroots:
charroots[root] += 1
# We need to keep track of terms so we can run collect() at the end.
# This is necessary for constantsimp to work properly.
collectterms = []
gensols = []
conjugate_roots = [] # used to prevent double-use of conjugate roots
# Loop over roots in theorder provided by roots/rootof...
for root in chareqroots:
# but don't repoeat multiple roots.
if root not in charroots:
continue
multiplicity = charroots.pop(root)
for i in range(multiplicity):
if chareq_is_complex:
gensols.append(x**i * exp(root * x))
collectterms = [(i, root, 0)] + collectterms
continue
reroot = re(root)
imroot = im(root)
if imroot.has(atan2) and reroot.has(atan2):
# Remove this condition when re and im stop returning
# circular atan2 usages.
gensols.append(x**i * exp(root * x))
collectterms = [(i, root, 0)] + collectterms
else:
if root in conjugate_roots:
collectterms = [(i, reroot, imroot)] + collectterms
continue
if imroot == 0:
gensols.append(x**i * exp(reroot * x))
collectterms = [(i, reroot, 0)] + collectterms
continue
conjugate_roots.append(conjugate(root))
gensols.append(x**i * exp(reroot * x) * sin(abs(imroot) * x))
gensols.append(x**i * exp(reroot * x) * cos(imroot * x))
# This ordering is important
collectterms = [(i, reroot, imroot)] + collectterms
return gensols, collectterms