def assert_ok(model, guide, elbo, *args, **kwargs):
"""
Assert that inference works without warnings or errors.
"""
pyro.get_param_store().clear()
adam = optim.Adam({"lr": 1e-6})
inference = infer.SVI(model, guide, adam, elbo)
for i in range(2):
inference.step(*args, **kwargs)
def assert_error(model, guide, elbo, match=None):
"""
Assert that inference fails with an error.
"""
pyro.get_param_store().clear()
adam = optim.Adam({"lr": 1e-6})
inference = infer.SVI(model, guide, adam, elbo)
with pytest.raises((NotImplementedError, UserWarning, KeyError, ValueError, RuntimeError),
match=match):
inference.step()
def assert_warning(model, guide, elbo):
"""
Assert that inference works but with a warning.
"""
pyro.get_param_store().clear()
adam = optim.Adam({"lr": 1e-6})
inference = infer.SVI(model, guide, adam, elbo)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter("always")
inference.step()
assert len(w), 'No warnings were raised'
for warning in w:
print(warning)
def main(args):
funsor.set_backend("torch")
# Define a basic model with a single Normal latent random variable `loc`
# and a batch of Normally distributed observations.
def model(data):
loc = pyro.sample("loc", dist.Normal(0., 1.))
with pyro.plate("data", len(data), dim=-1):
pyro.sample("obs", dist.Normal(loc, 1.), obs=data)
# Define a guide (i.e. variational distribution) with a Normal
# distribution over the latent random variable `loc`.
def guide(data):
guide_loc = pyro.param("guide_loc", torch.tensor(0.))
guide_scale = pyro.param("guide_scale", torch.tensor(1.),
constraint=constraints.positive)
pyro.sample("loc", dist.Normal(guide_loc, guide_scale))
# Generate some data.
torch.manual_seed(0)
data = torch.randn(100) + 3.0
# Because the API in minipyro matches that of Pyro proper,
# training code works with generic Pyro implementations.
with pyro_backend(args.backend), interpretation(MonteCarlo()):
# Construct an SVI object so we can do variational inference on our
# model/guide pair.
Elbo = infer.JitTrace_ELBO if args.jit else infer.Trace_ELBO
elbo = Elbo()
adam = optim.Adam({"lr": args.learning_rate})
svi = infer.SVI(model, guide, adam, elbo)
# Basic training loop
pyro.get_param_store().clear()
for step in range(args.num_steps):
loss = svi.step(data)
if args.verbose and step % 100 == 0:
print("step {} loss = {}".format(step, loss))
# Report the final values of the variational parameters
# in the guide after training.
if args.verbose:
for name in pyro.get_param_store():
value = pyro.param(name).data
print("{} = {}".format(name, value.detach().cpu().numpy()))
# For this simple (conjugate) model we know the exact posterior. In
# particular we know that the variational distribution should be
# centered near 3.0. So let's check this explicitly.
assert (pyro.param("guide_loc") - 3.0).abs() < 0.1
def test_gaussian_probit_hmm_smoke(exact, jit):
def model(data):
T, N, D = data.shape # time steps, individuals, features
# Gaussian initial distribution.
init_loc = pyro.param("init_loc", torch.zeros(D))
init_scale = pyro.param("init_scale",
1e-2 * torch.eye(D),
constraint=constraints.lower_cholesky)
# Linear dynamics with Gaussian noise.
trans_const = pyro.param("trans_const", torch.zeros(D))
trans_coeff = pyro.param("trans_coeff", torch.eye(D))
noise = pyro.param("noise",
1e-2 * torch.eye(D),
constraint=constraints.lower_cholesky)
obs_plate = pyro.plate("channel", D, dim=-1)
with pyro.plate("data", N, dim=-2):
state = None
for t in range(T):
# Transition.
if t == 0:
loc = init_loc
scale_tril = init_scale
else:
loc = trans_const + funsor.torch.torch_tensordot(
trans_coeff, state, 1)
scale_tril = noise
state = pyro.sample("state_{}".format(t),
dist.MultivariateNormal(loc, scale_tril),
infer={"exact": exact})
# Factorial probit likelihood model.
with obs_plate:
pyro.sample("obs_{}".format(t),
dist.Bernoulli(logits=state["channel"]),
obs=data[t])
def guide(data):
pass
data = torch.distributions.Bernoulli(0.5).sample((3, 4, 2))
with pyro_backend("funsor"):
Elbo = infer.JitTraceEnum_ELBO if jit else infer.TraceEnum_ELBO
elbo = Elbo()
adam = optim.Adam({"lr": 1e-3})
svi = infer.SVI(model, guide, adam, elbo)
svi.step(data)
def train(model, guide, lr=1e-3, n_steps=1000, jit=True, verbose=False, **kwargs):
pyro.clear_param_store()
optimizer = optim.Adam({"lr": lr})
elbo = (
infer.JitTraceEnum_ELBO(max_plate_nesting=2)
if jit
else infer.TraceEnum_ELBO(max_plate_nesting=2)
)
svi = infer.SVI(model, guide, optimizer, elbo)
for step in range(n_steps):
svi.step(**kwargs)
if step % 100 == 99 and verbose:
values = tuple(f"{k}: {v}" for k, v in pyro.get_param_store().items())
print(values)
def main(args):
if args.cuda:
torch.set_default_tensor_type('torch.cuda.FloatTensor')
logging.info('Loading data')
data = poly.load_data(poly.JSB_CHORALES)
logging.info('-' * 40)
model = models[args.model]
logging.info('Training {} on {} sequences'.format(
model.__name__, len(data['train']['sequences'])))
sequences = data['train']['sequences']
lengths = data['train']['sequence_lengths']
# find all the notes that are present at least once in the training set
present_notes = ((sequences == 1).sum(0).sum(0) > 0)
# remove notes that are never played (we remove 37/88 notes)
sequences = sequences[..., present_notes]
if args.truncate:
lengths = lengths.clamp(max=args.truncate)
sequences = sequences[:, :args.truncate]
num_observations = float(lengths.sum())
pyro.set_rng_seed(args.seed)
pyro.clear_param_store()
pyro.enable_validation(__debug__)
# We'll train using MAP Baum-Welch, i.e. MAP estimation while marginalizing
# out the hidden state x. This is accomplished via an automatic guide that
# learns point estimates of all of our conditional probability tables,
# named probs_*.
guide = AutoDelta(
handlers.block(model,
expose_fn=lambda msg: msg["name"].startswith("probs_")))
# To help debug our tensor shapes, let's print the shape of each site's
# distribution, value, and log_prob tensor. Note this information is
# automatically printed on most errors inside SVI.
if args.print_shapes:
first_available_dim = -2 if model is model_0 else -3
guide_trace = handlers.trace(guide).get_trace(
sequences, lengths, args=args, batch_size=args.batch_size)
model_trace = handlers.trace(
handlers.replay(handlers.enum(model, first_available_dim),
guide_trace)).get_trace(sequences,
lengths,
args=args,
batch_size=args.batch_size)
logging.info(model_trace.format_shapes())
# Bind non-PyTorch parameters to make these functions jittable.
model = functools.partial(model, args=args)
guide = functools.partial(guide, args=args)
# Enumeration requires a TraceEnum elbo and declaring the max_plate_nesting.
# All of our models have two plates: "data" and "tones".
optimizer = optim.Adam({'lr': args.learning_rate})
if args.tmc:
if args.jit and not args.funsor:
raise NotImplementedError(
"jit support not yet added for TraceTMC_ELBO")
Elbo = infer.JitTraceTMC_ELBO if args.jit else infer.TraceTMC_ELBO
elbo = Elbo(max_plate_nesting=1 if model is model_0 else 2)
tmc_model = handlers.infer_config(model, lambda msg: {
"num_samples": args.tmc_num_samples,
"expand": False
} if msg["infer"].get("enumerate", None) == "parallel" else {}
) # noqa: E501
svi = infer.SVI(tmc_model, guide, optimizer, elbo)
else:
Elbo = infer.JitTraceEnum_ELBO if args.jit else infer.TraceEnum_ELBO
elbo = Elbo(max_plate_nesting=1 if model is model_0 else 2,
strict_enumeration_warning=True,
jit_options={"time_compilation": args.time_compilation})
svi = infer.SVI(model, guide, optimizer, elbo)
# We'll train on small minibatches.
logging.info('Step\tLoss')
for step in range(args.num_steps):
loss = svi.step(sequences, lengths, batch_size=args.batch_size)
logging.info('{: >5d}\t{}'.format(step, loss / num_observations))
if args.jit and args.time_compilation:
logging.debug('time to compile: {} s.'.format(
elbo._differentiable_loss.compile_time))
# We evaluate on the entire training dataset,
# excluding the prior term so our results are comparable across models.
train_loss = elbo.loss(model,
guide,
sequences,
lengths,
batch_size=sequences.shape[0],
include_prior=False)
logging.info('training loss = {}'.format(train_loss / num_observations))
# Finally we evaluate on the test dataset.
logging.info('-' * 40)
logging.info('Evaluating on {} test sequences'.format(
len(data['test']['sequences'])))
sequences = data['test']['sequences'][..., present_notes]
lengths = data['test']['sequence_lengths']
if args.truncate:
lengths = lengths.clamp(max=args.truncate)
num_observations = float(lengths.sum())
# note that since we removed unseen notes above (to make the problem a bit easier and for
# numerical stability) this test loss may not be directly comparable to numbers
# reported on this dataset elsewhere.
test_loss = elbo.loss(model,
guide,
sequences,
lengths,
batch_size=sequences.shape[0],
include_prior=False)
logging.info('test loss = {}'.format(test_loss / num_observations))
# We expect models with higher capacity to perform better,
# but eventually overfit to the training set.
capacity = sum(
value.reshape(-1).size(0) for value in pyro.get_param_store().values())
logging.info('model_{} capacity = {} parameters'.format(
args.model, capacity))
