def update_fn(opt, lr, images, labels, rng):
"""Update step."""
measurements = {}
# Get device-specific loss rng.
rng, rng_model = jax.random.split(rng, 2)
rng_model_local = jax.random.fold_in(rng_model,
jax.lax.axis_index('batch'))
rng_model_local, diag_noise_rng, standard_noise_rng = jax.random.split(
rng_model_local, num=3)
def loss_fn(params, images, labels):
logits, _ = model.apply({'params': flax.core.freeze(params)},
images,
train=True,
rngs={
'dropout':
rng_model_local,
'diag_noise_samples':
diag_noise_rng,
'standard_norm_noise_samples':
standard_noise_rng
})
label_indices = config.get('label_indices')
if label_indices:
logits = logits[:, label_indices]
return getattr(train_utils,
config.get('loss', 'sigmoid_xent'))(logits=logits,
labels=labels)
# Implementation considerations compared and summarized at
# https://docs.google.com/document/d/1g3kMEvqu1DOawaflKNyUsIoQ4yIVEoyE5ZlIPkIl4Lc/edit?hl=en#
l, g = train_utils.accumulate_gradient(jax.value_and_grad(loss_fn),
opt.target, images, labels,
config.get('grad_accum_steps'))
l, g = jax.lax.pmean((l, g), axis_name='batch')
# Log the gradient norm only if we need to compute it anyways (clipping)
# or if we don't use grad_accum_steps, as they interact badly.
if config.get('grad_accum_steps',
1) == 1 or config.get('grad_clip_norm'):
grads, _ = jax.tree_flatten(g)
l2_g = jnp.sqrt(sum([jnp.vdot(p, p) for p in grads]))
measurements['l2_grads'] = l2_g
# Optionally resize the global gradient to a maximum norm. We found this
# useful in some cases across optimizers, hence it's in the main loop.
if config.get('grad_clip_norm'):
g_factor = jnp.minimum(1.0, config.grad_clip_norm / l2_g)
g = jax.tree_map(lambda p: g_factor * p, g)
opt = opt.apply_gradient(g, learning_rate=lr)
opt = opt.replace(target=weight_decay_fn(opt.target, lr))
params, _ = jax.tree_flatten(opt.target)
measurements['l2_params'] = jnp.sqrt(
sum([jnp.vdot(p, p) for p in params]))
return opt, l, rng, measurements
def update_fn(opt, lr, images, labels, rng):
"""Update step. Copy to deterministic_utils.py whenever changes are made!"""
measurements = {}
# Split rng and return next_rng for the following step.
rng, next_rng = jax.random.split(rng, 2)
rng_local = jax.random.fold_in(rng, jax.lax.axis_index('batch'))
def loss_fn(params, images, labels):
logits, _ = model.apply({'params': flax.core.freeze(params)},
images,
train=True,
rngs={'dropout': rng_local})
label_indices = config.get('label_indices')
if label_indices:
logits = logits[:, label_indices]
loss = getattr(train_utils,
config.get('loss', 'sigmoid_xent'))(logits=logits,
labels=labels)
return loss, logits
# Implementation considerations compared and summarized at
# https://docs.google.com/document/d/1g3kMEvqu1DOawaflKNyUsIoQ4yIVEoyE5ZlIPkIl4Lc/edit?hl=en#
(l, logits), g = train_utils.accumulate_gradient(
jax.value_and_grad(loss_fn, has_aux=True), opt.target, images,
labels, config.get('grad_accum_steps'))
l, g = jax.lax.pmean((l, g), axis_name='batch')
measurements['training_loss'] = l
# Log the gradient norm only if we need to compute it anyways (clipping)
# or if we don't use grad_accum_steps, as they interact badly.
if config.get('grad_accum_steps',
1) == 1 or config.get('grad_clip_norm'):
grads, _ = jax.tree_flatten(g)
l2_g = jnp.sqrt(sum([jnp.vdot(p, p) for p in grads]))
measurements['l2_grads'] = l2_g
# Optionally resize the global gradient to a maximum norm. We found this
# useful in some cases across optimizers, hence it's in the main loop.
if config.get('grad_clip_norm'):
g_factor = jnp.minimum(1.0, config.grad_clip_norm / l2_g)
g = jax.tree_util.tree_map(lambda p: g_factor * p, g)
opt = opt.apply_gradient(g, learning_rate=lr)
opt = opt.replace(target=weight_decay_fn(opt.target, lr))
params, _ = jax.tree_flatten(opt.target)
measurements['l2_params'] = jnp.sqrt(
sum([jnp.vdot(p, p) for p in params]))
top1_idx = jnp.argmax(logits, axis=1)
top1_correct = jnp.take_along_axis(labels, top1_idx[:, None],
axis=1)[:, 0]
prec1 = jax.lax.psum(jnp.sum(top1_correct),
axis_name='batch') / batch_size
measurements['training_prec@1'] = prec1
measurements['learning_rate'] = lr
return opt, next_rng, measurements
def update_fn(opt, lr, images, labels, rng):
"""Update step."""
measurements = {}
# Get device-specific loss rng.
rng, rng_model = jax.random.split(rng, 2)
rng_model_local = jax.random.fold_in(rng_model,
jax.lax.axis_index('batch'))
def loss_fn(params, images, labels):
logits, _ = model.apply({'params': flax.core.freeze(params)},
images,
train=True,
rngs={'dropout': rng_model_local})
return getattr(train_utils,
config.get('loss', 'sigmoid_xent'))(logits=logits,
labels=labels)
# Implementation considerations compared and summarized at
# https://docs.google.com/document/d/1g3kMEvqu1DOawaflKNyUsIoQ4yIVEoyE5ZlIPkIl4Lc/edit?hl=en#
l, g = train_utils.accumulate_gradient(jax.value_and_grad(loss_fn),
opt.target, images, labels,
config.get('grad_accum_steps'))
l, g = jax.lax.pmean((l, g), axis_name='batch')
# Log the gradient norm only if we need to compute it anyways (clipping)
# or if we don't use grad_accum_steps, as they interact badly.
if config.get('grad_accum_steps',
1) == 1 or grad_clip_norm is not None:
grads, _ = jax.tree_flatten(g)
l2_g = jnp.sqrt(sum([jnp.vdot(p, p) for p in grads]))
measurements['l2_grads'] = l2_g
# Optionally resize the global gradient to a maximum norm. We found this
# useful in some cases across optimizers, hence it's in the main loop.
if grad_clip_norm is not None:
g_factor = jnp.minimum(1.0, grad_clip_norm / l2_g)
g = jax.tree_util.tree_map(lambda p: g_factor * p, g)
opt = opt.apply_gradient(g, learning_rate=lr)
decay_rules = weight_decay or []
if isinstance(decay_rules, numbers.Number):
decay_rules = [('.*kernel.*', decay_rules)]
sched_m = lr / config.lr.base if config.get(
'weight_decay_decouple') else lr
def decay_fn(v, wd):
return (1.0 - sched_m * wd) * v
opt = opt.replace(target=train_utils.tree_map_with_regex(
decay_fn, opt.target, decay_rules))
params, _ = jax.tree_flatten(opt.target)
measurements['l2_params'] = jnp.sqrt(
sum([jnp.vdot(p, p) for p in params]))
return opt, l, rng, measurements