def undecimate(field, original_field, profclass=PolyRingOverField):
field = GF2QuotientRing.cast(field)
original_field = GF2QuotientRing.cast(original_field)
prof = profclass(original_field)
p = [(field.coeffs >> k) & 1 for k in range(field.degree+1)]
f = find_linear_factor(prof, p)
j = original_field.lograw(f[0])
return coset_representative(j, field.degree)
def __init__(self, field):
self.field = GF2QuotientRing.cast(field);