def get_parameter_and_state_names(self, layer):
# Store the names of the parameters for the scan loop
with make_functional_modules([layer]) as ([apply_fun], \
params, \
(state, constants, rng_seq), \
finalize):
bundle_name = current_bundle_name()
# Filter out the params and states that aren't a part of this repeat
filtered_params = {
key: val
for (key, val) in params.items() if key.startswith(bundle_name)
}
filtered_state = {
key: val
for (key, val) in state.items() if key.startswith(bundle_name)
}
# Order the parameters correctly and separate the keys from values
sorted_params = sorted(filtered_params.items(), key=lambda x: x[0])
sorted_state = sorted(filtered_state.items(), key=lambda x: x[0])
param_names, param_vals = zip(*sorted_params)
param_shapes = util.tree_shapes(param_vals)
if len(sorted_state) == 0:
state_names = ()
state_shapes = ()
else:
state_names, state_vals = zip(*sorted_state)
state_shapes = util.tree_shapes(state_vals)
finalize(params, (state, constants, rng_seq))
return (param_names, state_names), (param_shapes, state_shapes)
def flow_norm_init(self,
inputs: Mapping[str, jnp.ndarray],
rng: jnp.ndarray=None,
sample: Optional[bool]=False,
**kwargs):
""" Initialize this layer so that its outputs are normally distributed
"""
# Check if we've set flow norm (will be False the first time)
flow_norm_set = get_constant("flow_norm_set", False, do_not_set=True)
# Set that we're checking
get_constant("flow_norm_set", True, do_not_set=False)
if not flow_norm_set:
# Train this layer over the input batch to generate a unit normal output
def loss_fun(inputs, rng, sample=False, **kwargs):
outputs = self(inputs, rng, sample=sample, **kwargs)
z = outputs["x"]
@self.auto_batch
def unit_gaussian(z):
return -0.5*jnp.sum(z.ravel()**2) # + const
log_pz = unit_gaussian(z)
log_px = log_pz + outputs["log_det"]
return -log_px.mean()
with make_functional_modules([loss_fun]) as ([apply_fun], \
params, \
state, \
finalize_params_and_state):
import optax
opt_init, opt_update = optax.adam(learning_rate=1e-4)
opt_state = opt_init(params)
opt_update = jit(opt_update)
grad_fun = jax.value_and_grad(apply_fun, has_aux=True)
grad_fun = partial(grad_fun, sample=sample, **kwargs)
grad_fun = jit(grad_fun)
import tqdm
pbar = tqdm.tqdm(list(enumerate(random.split(rng, 200))))
for i, rng in pbar:
(loss, state), grad = grad_fun(params, state, inputs, rng)
updates, opt_state = opt_update(grad, opt_state, params)
if jnp.any(jnp.isnan(jax.flatten_util.ravel_pytree(updates)[0])):
break
params = jit(optax.apply_updates)(params, updates)
pbar.set_description(f"loss: {loss}")
finalize_params_and_state(params, state)
def forward(self, x, rng):
self.init_if_needed(x, rng)
batch_info = self.unbatched_input_shapes["x"], self.batch_shape
fun = partial(self.auto_batched_res_block, update_params=False)
with make_functional_modules([fun]) as ([apply_fun], \
params, \
state, \
finalize):
if self.use_trace_estimator:
z, log_det = res_flow_sliced_estimate(apply_fun, params, state,
x, rng, batch_info)
else:
z, log_det = res_flow_estimate(apply_fun, params, state, x,
rng, batch_info)
finalize(params, state)
return z, log_det
def invert(self, z, rng):
self.init_if_needed(z, rng)
# State will be held constant during the fixed point iterations
fun = partial(self.auto_batched_res_block, update_params=False)
with make_functional_modules([fun]) as ([apply_fun], \
params, \
state, \
finalize):
# Make sure we don't use a different random key at every step of the fixed point iterations.
deterministic_apply_fun = lambda params, state, x: apply_fun(
params, state, x, rng)
# Run the fixed point iterations to invert at z. We can do reverse-mode through this!
x = fixed_point(deterministic_apply_fun, params, state, z, rng)
# Update the Haiku global states
finalize(params, state)
return x
def forward(self, x, rng, update_params):
self.init_if_needed(x, rng)
batch_info = self.unbatched_input_shapes["x"], self.batch_shape
with make_functional_modules([self.auto_batched_res_block]) as ([apply_fun], \
params, \
state, \
finalize):
if self.use_trace_estimator:
z, log_det, state = res_flow_sliced_estimate(
apply_fun, params, state, x, rng, batch_info)
else:
z, log_det, state = res_flow_estimate(apply_fun, params, state,
x, rng, batch_info)
# Ensure that we don't backprop through state (this shouldn't affect anything)
state = jax.lax.stop_gradient(state)
# Update the Haiku global states
finalize(params, state)
return z, log_det
def call(self,
inputs: Mapping[str, jnp.ndarray],
rng: jnp.ndarray = None,
sample: Optional[bool] = False,
no_scan: bool = False,
accumulate: Iterable[str] = ["log_det", "aux_loss"],
**kwargs) -> Mapping[str, jnp.ndarray]:
if Layer._is_initializing:
return self.call_no_scan(inputs, rng, sample=sample, **kwargs)
# Want to make sure that we're passing all inputs/outputs to the next layer
final_outputs = inputs.copy()
# Need to get the funcitonal apply fun
with make_functional_modules([self.layer_create_fun()]) as ([apply_fun], \
params, \
(state, constants, rng_seq), \
finalize):
# Retrieve the hashes of the names of the parameters and states for the layer call
param_hashes, state_hashes = get_constant(
"param_state_name_hashes", None)
# Batch together the parameters and state across the repeated layers
scan_params = _batch_repeated_layers(params, param_hashes)
scan_params = data_structures.to_immutable_dict(scan_params)
scan_state = _batch_repeated_layers(state, state_hashes)
# Reverse the order if we are sampling
if sample == True:
scan_params = jax.tree_map(lambda x: x[::-1], scan_params)
scan_state = jax.tree_map(lambda x: x[::-1], scan_state)
# Pass other inputs we might have through the network
shared_inputs = inputs.copy()
del shared_inputs["x"]
# Use a scan loop so that we only need to compile layer once!
def scan_body(carry, scan_inputs):
x = carry
params, state, rng = scan_inputs
# Bundle the non-parameter state together
bundled_state = (state, constants, rng_seq)
# Make sure that we're passing all of the inputs (such as labels) to the layer
inputs = shared_inputs.copy()
inputs["x"] = x
# Run the function
outputs, bundled_state = apply_fun(params,
bundled_state,
inputs,
rng,
sample=sample,
**kwargs)
# Retrieve the state because it might have changed
state, _, _ = bundled_state
# Return the stuff we need
x = outputs["x"]
del outputs["x"]
return x, (outputs, state)
# Run the scan function
rngs = random.split(
rng,
self.n_repeats) if rng is not None else [None] * self.n_repeats
x, (batched_outputs, batched_updated_state) = jax.lax.scan(
scan_body, inputs["x"], (scan_params, scan_state, rngs))
# Reverse the updated state if we are sampling
if sample == True:
batched_updated_state = jax.tree_map(lambda x: x[::-1],
batched_updated_state)
# Search through the outputs to find things we want to accumulate
accumulated_outputs = {}
for name in accumulate:
if name in batched_outputs:
accumulated_outputs[name] = batched_outputs[name].sum(
axis=0)
del batched_outputs[name]
# Convert the output of the scan into the same state data structure that was passed in.
hash_map = {hash(k): k for k in state.keys()}
rev_hash_map = {k: hash(k) for k in state.keys()}
updated_state = state.copy()
for base_layer_name, pytree in batched_updated_state.items():
# Retrieve the names of each repeated layer
layer_names = [
hash_map[k]
for k in state_hashes[rev_hash_map[base_layer_name]]
]
# Split the batched parameters
leaves, treedef = jax.tree_flatten(
batched_updated_state[base_layer_name])
split_states = [
jax.tree_unflatten(treedef, [l[i] for l in leaves])
for i in range(self.n_repeats)
]
# Update the state dictionary
updated_state.update(dict(zip(layer_names, split_states)))
# Just in case
updated_state = jax.lax.stop_gradient(updated_state)
# Only state might be different
bundled_state = (updated_state, constants, rng_seq)
finalize(params, bundled_state)
outputs = {"x": x}
outputs.update(accumulated_outputs)
return outputs