def _imag_count_of_factor(f):
"""Return the number of imaginary roots for irreducible
univariate polynomial ``f``.
"""
terms = [(i, j) for (i, ), j in f.terms()]
if any(i % 2 for i, j in terms):
return 0
# update signs
even = [(i, I**i * j) for i, j in terms]
even = Poly.from_dict(dict(even), Dummy('x'))
return int(even.count_roots(-oo, oo))
def _imag_count_of_factor(f):
"""Return the number of imaginary roots for irreducible
univariate polynomial ``f``.
"""
terms = [(i, j) for (i,), j in f.terms()]
if any(i % 2 for i, j in terms):
return 0
# update signs
even = [(i, I**i*j) for i, j in terms]
even = Poly.from_dict(dict(even), Dummy('x'))
return int(even.count_roots(-oo, oo))
