114 lines
4.8 KiB
Python
114 lines
4.8 KiB
Python
import tensorflow as tf
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from stylegan2.utils import lerp
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from stylegan2.layers.mapping_block import Mapping
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from stylegan2.layers.synthesis_block import Synthesis
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class Generator(tf.keras.Model):
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def __init__(self, g_params, **kwargs):
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super(Generator, self).__init__(**kwargs)
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self.z_dim = g_params['z_dim']
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self.w_dim = g_params['w_dim']
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self.labels_dim = g_params['labels_dim']
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self.n_mapping = g_params['n_mapping']
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self.resolutions = g_params['resolutions']
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self.featuremaps = g_params['featuremaps']
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self.w_ema_decay = 0.995
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self.style_mixing_prob = 0.9
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self.n_broadcast = len(self.resolutions) * 2
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self.mixing_layer_indices = tf.range(self.n_broadcast, dtype=tf.int32)[tf.newaxis, :, tf.newaxis]
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self.g_mapping = Mapping(self.w_dim, self.labels_dim, self.n_mapping, name='g_mapping')
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self.broadcast = tf.keras.layers.Lambda(lambda x: tf.tile(x[:, tf.newaxis], [1, self.n_broadcast, 1]))
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self.synthesis = Synthesis(self.resolutions, self.featuremaps, name='g_synthesis')
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def build(self, input_shape):
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# w_avg
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self.w_avg = tf.Variable(tf.zeros(shape=[self.w_dim], dtype=tf.dtypes.float32), name='w_avg', trainable=False,
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synchronization=tf.VariableSynchronization.ON_READ,
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aggregation=tf.VariableAggregation.ONLY_FIRST_REPLICA)
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@tf.function
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def set_as_moving_average_of(self, src_net):
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beta, beta_nontrainable = 0.99, 0.0
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for cw, sw in zip(self.weights, src_net.weights):
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assert sw.shape == cw.shape
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# print('{} <=> {}'.format(cw.name, sw.name))
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if 'w_avg' in cw.name:
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cw.assign(lerp(sw, cw, beta_nontrainable))
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else:
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cw.assign(lerp(sw, cw, beta))
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return
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def update_moving_average_of_w(self, w_broadcasted):
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# compute average of current w
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batch_avg = tf.reduce_mean(w_broadcasted[:, 0], axis=0)
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# compute moving average of w and update(assign) w_avg
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self.w_avg.assign(lerp(batch_avg, self.w_avg, self.w_ema_decay))
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return
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def style_mixing_regularization(self, latents1, conditions, w_broadcasted1):
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# get another w and broadcast it
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latents2 = tf.random.normal(shape=tf.shape(latents1), dtype=tf.dtypes.float32)
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dlatents2 = self.g_mapping([latents2, conditions])
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w_broadcasted2 = self.broadcast(dlatents2)
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# find mixing limit index
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# mixing_cutoff_index = tf.cond(
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# pred=tf.less(tf.random.uniform([], 0.0, 1.0), self.style_mixing_prob),
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# true_fn=lambda: tf.random.uniform([], 1, self.n_broadcast, dtype=tf.dtypes.int32),
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# false_fn=lambda: tf.constant(self.n_broadcast, dtype=tf.dtypes.int32))
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if tf.random.uniform([], 0.0, 1.0) < self.style_mixing_prob:
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mixing_cutoff_index = tf.random.uniform([], 1, self.n_broadcast, dtype=tf.dtypes.int32)
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else:
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mixing_cutoff_index = tf.constant(self.n_broadcast, dtype=tf.dtypes.int32)
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# mix it
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mixed_w_broadcasted = tf.where(
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condition=tf.broadcast_to(self.mixing_layer_indices < mixing_cutoff_index, tf.shape(w_broadcasted1)),
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x=w_broadcasted1,
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y=w_broadcasted2)
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return mixed_w_broadcasted
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def truncation_trick(self, w_broadcasted, truncation_psi, truncation_cutoff=None):
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ones = tf.ones_like(self.mixing_layer_indices, dtype=tf.float32)
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tpsi = ones * truncation_psi
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if truncation_cutoff is None:
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truncation_coefs = tpsi
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else:
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indices = tf.range(self.n_broadcast)
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truncation_coefs = tf.where(condition=tf.less(indices, truncation_cutoff), x=tpsi, y=ones)
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truncated_w_broadcasted = lerp(self.w_avg, w_broadcasted, truncation_coefs)
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return truncated_w_broadcasted
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def call(self, inputs, ret_w_broadcasted=False, truncation_psi=1.0, truncation_cutoff=None, training=None, mask=None):
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latents, conditions = inputs
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dlatents = self.g_mapping([latents, conditions])
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w_broadcasted = self.broadcast(dlatents)
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if training:
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self.update_moving_average_of_w(w_broadcasted)
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w_broadcasted = self.style_mixing_regularization(latents, conditions, w_broadcasted)
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if not training:
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w_broadcasted = self.truncation_trick(w_broadcasted, truncation_psi, truncation_cutoff)
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image_out = self.synthesis(w_broadcasted)
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image_out = image_out * conditions[3][:,tf.newaxis,:,:]
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if ret_w_broadcasted:
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return image_out, w_broadcasted
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else:
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return image_out
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def compute_output_shape(self, input_shape):
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return input_shape[0][0], 3, self.resolutions[-1], self.resolutions[-1]
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