keras/demo_custom_jax_workflow.py
Francois Chollet 1a45e5cd17 Add demos
2023-04-18 15:46:57 -07:00

113 lines
3.0 KiB
Python

import jax
import numpy as np
from keras_core import Model
from keras_core import backend
from keras_core import initializers
from keras_core import layers
from keras_core import operations as ops
from keras_core import optimizers
class MyDense(layers.Layer):
def __init__(self, units, name=None):
super().__init__(name=name)
self.units = units
def build(self, input_shape):
input_dim = input_shape[-1]
w_shape = (input_dim, self.units)
w_value = initializers.GlorotUniform()(w_shape)
self.w = backend.Variable(w_value, name="kernel")
b_shape = (self.units,)
b_value = initializers.Zeros()(b_shape)
self.b = backend.Variable(b_value, name="bias")
def call(self, inputs):
return ops.matmul(inputs, self.w) + self.b
class MyModel(Model):
def __init__(self, hidden_dim, output_dim):
super().__init__()
self.dense1 = MyDense(hidden_dim)
self.dense2 = MyDense(hidden_dim)
self.dense3 = MyDense(output_dim)
def call(self, x):
x = self.dense1(x)
x = self.dense2(x)
return self.dense3(x)
def Dataset():
for _ in range(20):
yield (np.random.random((32, 128)), np.random.random((32, 16)))
def loss_fn(y_true, y_pred):
return ops.sum((y_true - y_pred) ** 2)
model = MyModel(hidden_dim=256, output_dim=16)
optimizer = optimizers.SGD(learning_rate=0.0001)
dataset = Dataset()
# # Build model
x = ops.convert_to_tensor(np.random.random((1, 128)))
model(x)
# Build optimizer
optimizer.build(model.trainable_variables)
def compute_loss_and_updates(
trainable_variables, non_trainable_variables, x, y
):
y_pred, non_trainable_variables = model.stateless_call(
trainable_variables, non_trainable_variables, x
)
loss = loss_fn(y, y_pred)
return loss, non_trainable_variables
grad_fn = jax.value_and_grad(compute_loss_and_updates, has_aux=True)
@jax.jit
def train_step(state, data):
trainable_variables, non_trainable_variables, optimizer_variables = state
x, y = data
(loss, non_trainable_variables), grads = grad_fn(
trainable_variables, non_trainable_variables, x, y
)
trainable_variables, optimizer_variables = optimizer.stateless_apply(
grads, trainable_variables, optimizer_variables
)
# Return updated state
return loss, (
trainable_variables,
non_trainable_variables,
optimizer_variables,
)
trainable_variables = model.trainable_variables
non_trainable_variables = model.non_trainable_variables
optimizer_variables = optimizer.variables
state = trainable_variables, non_trainable_variables, optimizer_variables
# Training loop
for data in dataset:
loss, state = train_step(state, data)
print("Loss:", loss)
# Post-processing model state update
for variable, value in zip(model.trainable_variables, trainable_variables):
variable.assign(value)
for variable, value in zip(
model.non_trainable_variables, non_trainable_variables
):
variable.assign(value)