def __init__(self, n):
"""
Initialize ``self``.
EXAMPLES::
sage: G = groups.matrix.BinaryDihedral(4)
sage: TestSuite(G).run()
"""
self._n = n
if n % 2 == 0:
R = CyclotomicField(2 * n)
zeta = R.gen()
i = R.gen()**(n // 2)
else:
R = CyclotomicField(4 * n)
zeta = R.gen()**2
i = R.gen()**n
MS = MatrixSpace(R, 2)
zero = R.zero()
gens = [MS([zeta, zero, zero, ~zeta]), MS([zero, i, i, zero])]
from sage.libs.gap.libgap import libgap
gap_gens = [libgap(matrix_gen) for matrix_gen in gens]
gap_group = libgap.Group(gap_gens)
FinitelyGeneratedMatrixGroup_gap.__init__(self,
ZZ(2),
R,
gap_group,
category=Groups().Finite())
def __init__(self, n):
"""
Initialize ``self``.
EXAMPLES::
sage: G = groups.matrix.BinaryDihedral(4)
sage: TestSuite(G).run()
"""
self._n = n
if n % 2 == 0:
R = CyclotomicField(2*n)
zeta = R.gen()
i = R.gen()**(n//2)
else:
R = CyclotomicField(4*n)
zeta = R.gen()**2
i = R.gen()**n
MS = MatrixSpace(R, 2)
zero = R.zero()
gens = [ MS([zeta, zero, zero, ~zeta]), MS([zero, i, i, zero]) ]
from sage.libs.gap.libgap import libgap
gap_gens = [libgap(matrix_gen) for matrix_gen in gens]
gap_group = libgap.Group(gap_gens)
FinitelyGeneratedMatrixGroup_gap.__init__(self, ZZ(2), R, gap_group, category=Groups().Finite())
