# Revision history [back]

Thanks to the kind and patient help of @rburing this finally seems to be working!

def berlekamp_basis(f):
"""
INPUT: f a monic squarefree polynomial in F_q[x]
OUTPUT: a list of polynomials hi in F_q[x] that represent
a basis of the Berlekamp algebra associated to f
"""
n = f.degree()
GFX = f.parent()
x = GFX.gen()
q = GFX.base().order()
GFX_quo_f = GFX.quotient(f)
g = []
for k in range(n):
basic_image = GFX_quo_f(x^(q*k)- x^k)
g.append(vector(basic_image))
H = matrix(g).transpose().right_kernel().basis()
H = [h.lift() for h in H]
return H


Thanks to the kind and patient help of @rburing this finally seems to be working!

vector2poly = lambda h: reduce(lambda a,b:a+b, [ci*x^i for i,ci in enumerate(h)])

def berlekamp_basis(f):
"""
INPUT: f a monic squarefree polynomial in F_q[x]
OUTPUT: a list of polynomials hi in F_q[x] that represent
a basis of the Berlekamp algebra associated to f
"""
n = f.degree()
GFX = f.parent()
x = GFX.gen()
q = GFX.base().order()
GFX_quo_f = GFX.quotient(f)
g = []
for k in range(n):
basic_image = GFX_quo_f(x^(q*k)- x^k)
g.append(vector(basic_image))
H = matrix(g).transpose().right_kernel().basis()
H = [h.lift() for h in H]
H = map(vector2poly, [h.lift() for h in H])
return H


Thanks to the kind and patient help of @rburing this finally seems to be working!

vector2poly = lambda h: reduce(lambda a,b:a+b, [ci*x^i for i,ci in enumerate(h)]) enumerate(h)])

def berlekamp_basis(f):
"""
INPUT: f a monic squarefree polynomial in F_q[x]
OUTPUT: a list of polynomials hi in F_q[x] that represent
a basis of the Berlekamp algebra associated to f
"""
n = f.degree()
GFX = f.parent()
x = GFX.gen()
q = GFX.base().order()
GFX_quo_f = GFX.quotient(f)
g = []
for k in range(n):
basic_image = GFX_quo_f(x^(q*k)- x^k)
g.append(vector(basic_image))
H = matrix(g).transpose().right_kernel().basis()
H = [h.lift() for h in H]
H = map(vector2poly, [h.lift() for h in H])
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