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import numpy as np |
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from tensorflow.python.ops import control_flow_ops, state_ops |
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from core.leras import nn |
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tf = nn.tf |
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class RMSprop(nn.OptimizerBase): |
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def __init__(self, lr=0.001, rho=0.9, lr_dropout=1.0, lr_cos=0, clipnorm=0.0, name=None, **kwargs): |
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super().__init__(name=name) |
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if name is None: |
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raise ValueError('name must be defined.') |
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self.lr_dropout = lr_dropout |
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self.lr_cos = lr_cos |
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self.lr = lr |
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self.rho = rho |
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self.clipnorm = clipnorm |
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with tf.device('/CPU:0') : |
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with tf.variable_scope(self.name): |
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self.iterations = tf.Variable(0, dtype=tf.int64, name='iters') |
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self.accumulators_dict = {} |
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self.lr_rnds_dict = {} |
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def get_weights(self): |
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return [self.iterations] + list(self.accumulators_dict.values()) |
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def initialize_variables(self, trainable_weights, vars_on_cpu=True, lr_dropout_on_cpu=False): |
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e = tf.device('/CPU:0') if vars_on_cpu else None |
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if e: e.__enter__() |
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with tf.variable_scope(self.name): |
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accumulators = { v.name : tf.get_variable ( f'acc_{v.name}'.replace(':','_'), v.shape, dtype=v.dtype, initializer=tf.initializers.constant(0.0), trainable=False) for v in trainable_weights } |
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self.accumulators_dict.update ( accumulators) |
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if self.lr_dropout != 1.0: |
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e = tf.device('/CPU:0') if lr_dropout_on_cpu else None |
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if e: e.__enter__() |
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lr_rnds = [ nn.random_binomial( v.shape, p=self.lr_dropout, dtype=v.dtype) for v in trainable_weights ] |
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if e: e.__exit__(None, None, None) |
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self.lr_rnds_dict.update ( { v.name : rnd for v,rnd in zip(trainable_weights,lr_rnds) } ) |
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if e: e.__exit__(None, None, None) |
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def get_update_op(self, grads_vars): |
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updates = [] |
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if self.clipnorm > 0.0: |
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norm = tf.sqrt( sum([tf.reduce_sum(tf.square(tf.cast(g, tf.float32))) for g,v in grads_vars])) |
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updates += [ state_ops.assign_add( self.iterations, 1) ] |
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for i, (g,v) in enumerate(grads_vars): |
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if self.clipnorm > 0.0: |
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g = self.tf_clip_norm(g, self.clipnorm, tf.cast(norm, g.dtype) ) |
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a = self.accumulators_dict[ v.name ] |
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new_a = self.rho * a + (1. - self.rho) * tf.square(g) |
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lr = tf.constant(self.lr, g.dtype) |
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if self.lr_cos != 0: |
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lr *= (tf.cos( tf.cast(self.iterations, g.dtype) * (2*3.1415926535/ float(self.lr_cos) ) ) + 1.0) / 2.0 |
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v_diff = - lr * g / (tf.sqrt(new_a) + np.finfo( g.dtype.as_numpy_dtype ).resolution ) |
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if self.lr_dropout != 1.0: |
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lr_rnd = self.lr_rnds_dict[v.name] |
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v_diff *= lr_rnd |
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new_v = v + v_diff |
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updates.append (state_ops.assign(a, new_a)) |
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updates.append (state_ops.assign(v, new_v)) |
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return control_flow_ops.group ( *updates, name=self.name+'_updates') |
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nn.RMSprop = RMSprop |
