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faceswap/lib/model/optimizers.py
torzdf 815c843f63
Simple backend unit tests (#1020)
* Add simple backend tests for lib.model
* Document lib.model
* Fix GMSD Loss for AMD
* Remove obsolete code from lib.model
2020-05-12 23:46:04 +01:00

146 lines
5 KiB
Python

#!/usr/bin/env python3
""" Optimizers for faceswap.py """
# Naming convention inherited from Keras so ignore invalid names
# pylint:disable=invalid-name
import logging
from keras import backend as K
from keras.optimizers import Adam as KerasAdam
logger = logging.getLogger(__name__) # pylint: disable=invalid-name
class Adam(KerasAdam):
"""Adapted Keras Adam Optimizer to allow support of calculations on CPU for Tensorflow.
Default parameters follow those provided in the original paper. Adapted from
https://github.com/iperov/DeepFaceLab
Parameters
----------
lr: float, optional
>= `0`. Learning rate. Default: `0.001`
beta_1: float, optional
`0` < beta < `1` Generally close to `1`. Default: `0.9`
beta_2: float, optional
`0` < beta < `1`. Generally close to `1`. Default: `0.999`
epsilon: float, optional
>= `0`. Fuzz factor. If ``None``, defaults to `K.epsilon()`. Default: ``None``
decay: float, optional
>= 0. Learning rate decay over each update. Default: `0`
amsgrad: bool, optional
``True`` to apply the AMSGrad variant of this algorithm from the paper "On the Convergence
of Adam and Beyond" otherwise ``False``. Default: ``False``
cpu_mode: bool, optional
Set to ``True`` to perform some of the calculations on CPU for Nvidia backends, otherwise
``False``. Default: ``False``
kwargs: dict
Any additional standard Keras optimizer keyword arguments
References
----------
- Adam - A Method for Stochastic Optimization - https://arxiv.org/abs/1412.6980v8
- On the Convergence of Adam and Beyond - https://openreview.net/forum?id=ryQu7f-RZ
"""
def __init__(self,
lr=0.001,
beta_1=0.9,
beta_2=0.999,
epsilon=None,
decay=0.,
amsgrad=False,
cpu_mode=False,
**kwargs):
super().__init__(lr, beta_1, beta_2, epsilon, decay, **kwargs)
self.cpu_mode = self._set_cpu_mode(cpu_mode)
@staticmethod
def _set_cpu_mode(cpu_mode):
""" Sets the CPU mode to False if not using Tensorflow, otherwise the given value.
Parameters
----------
cpu_mode: bool
Set to ``True`` to perform some of the calculations on CPU for Nvidia backends,
otherwise ``False``.
Returns
-------
bool
``True`` if some calculations should be performed on CPU otherwise ``False``
"""
retval = False if K.backend() != "tensorflow" else cpu_mode
logger.debug("Optimizer CPU Mode set to %s", retval)
return retval
def get_updates(self, loss, params):
""" Obtain the optimizer loss updates.
Parameters
----------
loss: list
List of tensors
params: list
List of tensors
Returns
-------
list
List of tensors
"""
grads = self.get_gradients(loss, params)
self.updates = [K.update_add(self.iterations, 1)]
lr = self.lr
if self.initial_decay > 0:
lr = lr * (1. / (1. + self.decay * K.cast(self.iterations,
K.dtype(self.decay))))
t = K.cast(self.iterations, K.floatx()) + 1
lr_t = lr * (K.sqrt(1. - K.pow(self.beta_2, t)) /
(1. - K.pow(self.beta_1, t)))
# Pass off to CPU if requested
if self.cpu_mode:
with K.tf.device("/cpu:0"):
ms, vs, vhats = self._update_1(params)
else:
ms, vs, vhats = self._update_1(params)
self.weights = [self.iterations] + ms + vs + vhats
for p, g, m, v, vhat in zip(params, grads, ms, vs, vhats):
m_t = (self.beta_1 * m) + (1. - self.beta_1) * g
v_t = (self.beta_2 * v) + (1. - self.beta_2) * K.square(g)
if self.amsgrad:
vhat_t = K.maximum(vhat, v_t)
p_t = p - lr_t * m_t / (K.sqrt(vhat_t) + self.epsilon)
self.updates.append(K.update(vhat, vhat_t))
else:
p_t = p - lr_t * m_t / (K.sqrt(v_t) + self.epsilon)
self.updates.append(K.update(m, m_t))
self.updates.append(K.update(v, v_t))
new_p = p_t
# Apply constraints.
if getattr(p, 'constraint', None) is not None:
new_p = p.constraint(new_p)
self.updates.append(K.update(p, new_p))
return self.updates
def _update_1(self, params):
""" Perform the first update. Run under CPU context if running on Tensorflow and CPU mode
is enabled, otherwise run on the default device. """
ms = [K.zeros(K.int_shape(p), dtype=K.dtype(p)) for p in params]
vs = [K.zeros(K.int_shape(p), dtype=K.dtype(p)) for p in params]
if self.amsgrad:
vhats = [K.zeros(K.int_shape(p), dtype=K.dtype(p)) for p in params]
else:
vhats = [K.zeros(1) for _ in params]
return ms, vs, vhats