BKZ Reduction RuntimeError Aborted

[WZHYX]

When I utilise the BKZ algorithm on a basis as shown in the code below, I will receive a runtime error. The error message produced is very vague and I am not able to solve the issue

Edit: After running the code again, I got another error that states "infinite loop in babai". Where does this error originate from?

Code

def small_poly_vector(size, high=2, low=-1):
    v = [R(list(np.random.randint(low, high, N))) for _ in range(size)]
    if size==1:
        return v[0]
    return vector(v)

Q = 3329
N = 64
k = 2
eta1 = 2
eta2 = 2

HALF_Q = int((Q + 1) / 2)
PR.<x> = PolynomialRing(GF(Q))
R.<z> = PR.quotient_ring(x^N + 1)

A = random_matrix(R, k, k)
s = small_poly_vector(k, eta1)
e = small_poly_vector(k, eta2)
t = A*s+e

A_t = matrix(QQ, 2*N+1, 2*N)
A_t[:N,:N] = A[0][0].matrix()
A_t[N:2*N,:N] = A[0][1].matrix()
A_t[:N,N:] = A[1][0].matrix()
A_t[N:2*N,N:] = A[1][1].matrix()
A_t[2*N] = [int(i) for i in t[0]]+[int(i) for i in t[1]]

lattice_size = 4*N+1
B = matrix(QQ, lattice_size, lattice_size)
B[:2*N,:2*N] = Q * identity_matrix(QQ, 2*N, 2*N)
B[2*N:,:2*N] = A_t
B[2*N:,2*N:] = identity_matrix(QQ, 2*N+1, 2*N+1)

B = IntegerMatrix.from_matrix([[int(entry) for entry in row] for row in B])
BKZ.reduction(B, o=BKZ.Param(block_size=20))
reduced_matrix = [[B[i, j] for j in range(B.ncols)] for i in range(B.nrows)]
shortest_vector = reduced_matrix[0]

Error message

[dimpase]

It might be insufficient precision of floats used by default. Cf.

sage: BKZ.reduction(B, o=BKZ.Param(block_size=10),float_type="mpfr", precision=53)
terminate called recursively

• which is the error you get, but

sage: BKZ.reduction(B, o=BKZ.Param(block_size=10),float_type="mpfr", precision=70)

doesn't terminate quickly (I didn't wait for it to finish)