def test_sigmoid(self):
x1 = Variable(0, name='x1')
x2 = AutoDiff.sigmoid(x1)
assert x2.val == 0.5
assert x2.der == {'x1': 0.25}
def test_sigmoid(self):
x1 = Variable(0, name='x1')
z1 = AutoDiff.sigmoid(x1)
assert z1.der2['x1x1'][0] == 0
