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17 changes: 9 additions & 8 deletions tf_utils/adamax.py
Original file line number Diff line number Diff line change
Expand Up @@ -8,14 +8,12 @@

class AdamaxOptimizer(optimizer.Optimizer):
"""Optimizer that implements the Adamax algorithm.

See [Kingma et. al., 2014](http://arxiv.org/abs/1412.6980)
([pdf](http://arxiv.org/pdf/1412.6980.pdf)).

@@__init__
"""

def __init__(self, learning_rate=0.001, beta1=0.9, beta2=0.999, use_locking=False, name="Adamax"):
def __init__(self, learning_rate=0.002, beta1=0.9, beta2=0.999, use_locking=False, name="Adamax"):
super(AdamaxOptimizer, self).__init__(use_locking, name)
self._lr = learning_rate
self._beta1 = beta1
Expand All @@ -36,6 +34,7 @@ def _create_slots(self, var_list):
for v in var_list:
self._zeros_slot(v, "m", self._name)
self._zeros_slot(v, "v", self._name)
self._zeros_slot(v, "t", self._name)

def _apply_dense(self, grad, var):
lr_t = math_ops.cast(self._lr_t, var.dtype.base_dtype)
Expand All @@ -45,15 +44,17 @@ def _apply_dense(self, grad, var):
eps = 1e-7 # Can't use 1e-8 due to underflow -- not sure if it makes a big difference.
else:
eps = 1e-8

v = self.get_slot(var, "v")
v_t = v.assign(beta1_t * v + (1. - beta1_t) * grad)
m = self.get_slot(var, "m")
m_t = m.assign(tf.maximum(beta2_t * m + eps, tf.abs(grad)))
g_t = v_t / m_t
m_t = m.assign(tf.maximum(beta2_t * m,tf.abs(grad)+eps))
t=self.get_slot(var,"t")
t_t=t.assign(t+1)
g_t = lr_t/(1-beta1_t**t_t)*v_t/m_t

var_update = state_ops.assign_sub(var, lr_t * g_t)
return control_flow_ops.group(*[var_update, m_t, v_t])
var_update = state_ops.assign_sub(var,g_t)
return control_flow_ops.group(*[var_update, t_t ,m_t, v_t])

def _apply_sparse(self, grad, var):
raise NotImplementedError("Sparse gradient updates are not supported.")