def test_inverse3(self):
a = Matrix([[9, 3, 0, 9], [-5, -2, -6, -3], [-4, 9, 6, 4],
[-7, 6, 6, 2]])
assert a.inverse() == Matrix([[-0.04074, -0.07778, 0.14444, -0.22222],
[-0.07778, 0.03333, 0.36667, -0.33333],
[-0.02901, -0.14630, -0.10926, 0.12963],
[0.17778, 0.06667, -0.26667, 0.33333]])
def test_inverse2(self):
a = Matrix([[8, -5, 9, 2], [7, 5, 6, 1], [-6, 0, 9, 6],
[-3, 0, -9, -4]])
assert a.inverse() == Matrix([[-0.15385, -0.15385, -0.28205, -0.53846],
[-0.07692, 0.12308, 0.02564, 0.03077],
[0.35897, 0.35897, 0.43590, 0.92308],
[-0.69231, -0.69231, -0.76923,
-1.92308]])
def test_inverse(self):
a = Matrix([[-5, 2, 6, -8], [1, -5, 1, 8], [7, 7, -6, -7],
[1, -3, 7, 4]])
b = a.inverse()
assert a.determinant() == 532
assert a.cofactor(2, 3) == -160
assert b[3, 2] == -160 / 532
assert a.cofactor(3, 2) == 105
assert b[2, 3] == 105 / 532
assert b == Matrix([[0.21805, 0.45113, 0.24060, -0.04511],
[-0.80827, -1.45677, -0.44361, 0.52068],
[-0.07895, -0.22368, -0.05263, 0.19737],
[-0.52256, -0.81391, -0.30075, 0.30639]])
def test_multiply_product_by_its_inverse(self):
a = Matrix([[3, -9, 7, 3], [3, -8, 2, -9], [-4, 4, 4, 1],
[-6, 5, -1, 1]])
b = Matrix([[8, 2, 2, 2], [3, -1, 7, 0], [7, 0, 5, 4], [6, -2, 0, 5]])
c = a * b
assert c * b.inverse() == a