def test_focal_loss(self):
with self.cached_session():
logits = np.array([[22, 23, 24]], dtype=np.float32)
labels = np.array([2], dtype=np.int32)
ce_loss = loss_utils.cross_entropy(
logits=tf.constant(logits),
input_length=None,
labels=tf.constant(labels),
label_length=None)
fl_loss0 = loss_utils.focal_loss(
logits=tf.constant(logits),
labels=tf.constant(labels),
gamma = 0)
self.assertAllClose(fl_loss0.eval(), 0.407606, rtol=1e-06, atol=1e-6)
self.assertAllClose(fl_loss0.eval(), ce_loss.eval(), rtol=1e-07, atol=1e-7)
fl_loss2 = loss_utils.focal_loss(
logits=tf.constant(logits),
labels=tf.constant(labels),
gamma = 2)
fl_loss5 = loss_utils.focal_loss(
logits=tf.constant(logits),
labels=tf.constant(labels),
gamma = 5)
self.assertAllClose(fl_loss2.eval(), 0.045677, rtol=1e-06, atol=1e-6)
self.assertAllClose(fl_loss5.eval(), 0.001713, rtol=1e-06, atol=1e-6)
def call(self,
logits=None,
input_length=None,
labels=None,
label_length=None,
**kwargs):
del input_length
del label_length
return focal_loss(
logits=logits, labels=labels, gamma=self.gamma, name='focal_loss')