def test_log(self):
a = Variable(1.5)
c = a.log()
c.backward()
self.assertAlmostEqual(c.value, log(1.5))
self.assertAlmostEqual(a.d.value, 1 / 1.5)
def test_log(self):
a = Variable(1.5)
c = a.log()
self.assertAlmostEqual(c.value, log(1.5))