def eager_cat_homogeneous(name, part_name, *parts):
assert parts
output = parts[0].output
inputs = OrderedDict([(part_name, None)])
for part in parts:
assert part.output == output
assert part_name in part.inputs
inputs.update(part.inputs)
int_inputs = OrderedDict(
(k, v) for k, v in inputs.items() if v.dtype != "real")
real_inputs = OrderedDict(
(k, v) for k, v in inputs.items() if v.dtype == "real")
inputs = int_inputs.copy()
inputs.update(real_inputs)
discretes = []
info_vecs = []
precisions = []
for part in parts:
inputs[part_name] = part.inputs[part_name]
int_inputs[part_name] = inputs[part_name]
shape = tuple(d.size for d in int_inputs.values())
if isinstance(part, Gaussian):
discrete = None
gaussian = part
elif issubclass(type(part), GaussianMixture
): # TODO figure out why isinstance isn't working
discrete, gaussian = part.terms[0], part.terms[1]
discrete = ops.expand(align_tensor(int_inputs, discrete), shape)
else:
raise NotImplementedError("TODO")
discretes.append(discrete)
info_vec, precision = align_gaussian(inputs, gaussian)
info_vecs.append(ops.expand(info_vec, shape + (-1, )))
precisions.append(ops.expand(precision, shape + (-1, -1)))
if part_name != name:
del inputs[part_name]
del int_inputs[part_name]
dim = 0
info_vec = ops.cat(dim, *info_vecs)
precision = ops.cat(dim, *precisions)
inputs[name] = Bint[info_vec.shape[dim]]
int_inputs[name] = inputs[name]
result = Gaussian(info_vec, precision, inputs)
if any(d is not None for d in discretes):
for i, d in enumerate(discretes):
if d is None:
discretes[i] = ops.new_zeros(info_vecs[i],
info_vecs[i].shape[:-1])
discrete = ops.cat(dim, *discretes)
result = result + Tensor(discrete, int_inputs)
return result
def as_tensor(self):
# Fill gaps with zeros.
prototype = next(iter(self.parts.values()))
for i in _find_intervals(self.parts.keys(), self.shape[-1]):
if i not in self.parts:
self.parts[i] = ops.new_zeros(
prototype, self.shape[:-1] + (i[1] - i[0], ))
# Concatenate parts.
parts = [v for k, v in sorted(self.parts.items())]
result = ops.cat(-1, *parts)
if not get_tracing_state():
assert result.shape == self.shape
return result
def as_tensor(self):
# Fill gaps with zeros.
arbitrary_row = next(iter(self.parts.values()))
prototype = next(iter(arbitrary_row.values()))
js = set().union(*(part.keys() for part in self.parts.values()))
rows = _find_intervals(self.parts.keys(), self.shape[-2])
cols = _find_intervals(js, self.shape[-1])
for i in rows:
for j in cols:
if j not in self.parts[i]:
shape = self.shape[:-2] + (i[1] - i[0], j[1] - j[0])
self.parts[i][j] = ops.new_zeros(prototype, shape)
# Concatenate parts.
# TODO This could be optimized into a single .reshape().cat().reshape() if
# all inputs are contiguous, thereby saving a memcopy.
columns = {
i: ops.cat(-1, *[v for j, v in sorted(part.items())])
for i, part in self.parts.items()
}
result = ops.cat(-2, *[v for i, v in sorted(columns.items())])
if not get_tracing_state():
assert result.shape == self.shape
return result
def eager_cat_homogeneous(name, part_name, *parts):
assert parts
output = parts[0].output
inputs = OrderedDict([(part_name, None)])
for part in parts:
assert part.output == output
assert part_name in part.inputs
inputs.update(part.inputs)
tensors = []
for part in parts:
inputs[part_name] = part.inputs[part_name]
shape = tuple(d.size for d in inputs.values()) + output.shape
tensors.append(ops.expand(align_tensor(inputs, part), shape))
del inputs[part_name]
dim = 0
tensor = ops.cat(dim, *tensors)
inputs = OrderedDict([(name, Bint[tensor.shape[dim]])] +
list(inputs.items()))
return Tensor(tensor, inputs, dtype=output.dtype)
def eager_reduce(self, op, reduced_vars):
if op is ops.logaddexp:
# Marginalize out real variables, but keep mixtures lazy.
assert all(v in self.inputs for v in reduced_vars)
real_vars = frozenset(k for k, d in self.inputs.items()
if d.dtype == "real")
reduced_reals = reduced_vars & real_vars
reduced_ints = reduced_vars - real_vars
if not reduced_reals:
return None # defer to default implementation
inputs = OrderedDict((k, d) for k, d in self.inputs.items()
if k not in reduced_reals)
if reduced_reals == real_vars:
result = self.log_normalizer
else:
int_inputs = OrderedDict(
(k, v) for k, v in inputs.items() if v.dtype != 'real')
offsets, _ = _compute_offsets(self.inputs)
a = []
b = []
for key, domain in self.inputs.items():
if domain.dtype == 'real':
block = ops.new_arange(
self.info_vec, offsets[key],
offsets[key] + domain.num_elements, 1)
(b if key in reduced_vars else a).append(block)
a = ops.cat(-1, *a)
b = ops.cat(-1, *b)
prec_aa = self.precision[..., a[..., None], a]
prec_ba = self.precision[..., b[..., None], a]
prec_bb = self.precision[..., b[..., None], b]
prec_b = ops.cholesky(prec_bb)
prec_a = ops.triangular_solve(prec_ba, prec_b)
prec_at = ops.transpose(prec_a, -1, -2)
precision = prec_aa - ops.matmul(prec_at, prec_a)
info_a = self.info_vec[..., a]
info_b = self.info_vec[..., b]
b_tmp = ops.triangular_solve(info_b[..., None], prec_b)
info_vec = info_a - ops.matmul(prec_at, b_tmp)[..., 0]
log_prob = Tensor(
0.5 * len(b) * math.log(2 * math.pi) -
_log_det_tri(prec_b) + 0.5 * (b_tmp[..., 0]**2).sum(-1),
int_inputs)
result = log_prob + Gaussian(info_vec, precision, inputs)
return result.reduce(ops.logaddexp, reduced_ints)
elif op is ops.add:
for v in reduced_vars:
if self.inputs[v].dtype == 'real':
raise ValueError(
"Cannot sum along a real dimension: {}".format(
repr(v)))
# Fuse Gaussians along a plate. Compare to eager_add_gaussian_gaussian().
old_ints = OrderedDict(
(k, v) for k, v in self.inputs.items() if v.dtype != 'real')
new_ints = OrderedDict(
(k, v) for k, v in old_ints.items() if k not in reduced_vars)
inputs = OrderedDict((k, v) for k, v in self.inputs.items()
if k not in reduced_vars)
info_vec = Tensor(self.info_vec,
old_ints).reduce(ops.add, reduced_vars)
precision = Tensor(self.precision,
old_ints).reduce(ops.add, reduced_vars)
assert info_vec.inputs == new_ints
assert precision.inputs == new_ints
return Gaussian(info_vec.data, precision.data, inputs)
return None # defer to default implementation
def _eager_subs_real(self, subs, remaining_subs):
# Broadcast all component tensors.
subs = OrderedDict(subs)
int_inputs = OrderedDict(
(k, d) for k, d in self.inputs.items() if d.dtype != 'real')
tensors = [
Tensor(self.info_vec, int_inputs),
Tensor(self.precision, int_inputs)
]
tensors.extend(subs.values())
int_inputs, tensors = align_tensors(*tensors)
batch_dim = len(tensors[0].shape) - 1
batch_shape = broadcast_shape(*(x.shape[:batch_dim] for x in tensors))
(info_vec, precision), values = tensors[:2], tensors[2:]
offsets, event_size = _compute_offsets(self.inputs)
slices = [(k, slice(offset, offset + self.inputs[k].num_elements))
for k, offset in offsets.items()]
# Expand all substituted values.
values = OrderedDict(zip(subs, values))
for k, value in values.items():
value = value.reshape(value.shape[:batch_dim] + (-1, ))
if not get_tracing_state():
assert value.shape[-1] == self.inputs[k].num_elements
values[k] = ops.expand(value, batch_shape + value.shape[-1:])
# Try to perform a complete substitution of all real variables, resulting in a Tensor.
if all(k in subs for k, d in self.inputs.items() if d.dtype == 'real'):
# Form the concatenated value.
value = BlockVector(batch_shape + (event_size, ))
for k, i in slices:
if k in values:
value[..., i] = values[k]
value = value.as_tensor()
# Evaluate the non-normalized log density.
result = _vv(value, info_vec - 0.5 * _mv(precision, value))
result = Tensor(result, int_inputs)
assert result.output == Real
return Subs(result, remaining_subs) if remaining_subs else result
# Perform a partial substution of a subset of real variables, resulting in a Joint.
# We split real inputs into two sets: a for the preserved and b for the substituted.
b = frozenset(k for k, v in subs.items())
a = frozenset(k for k, d in self.inputs.items()
if d.dtype == 'real' and k not in b)
prec_aa = ops.cat(
-2, *[
ops.cat(
-1,
*[precision[..., i1, i2] for k2, i2 in slices if k2 in a])
for k1, i1 in slices if k1 in a
])
prec_ab = ops.cat(
-2, *[
ops.cat(
-1,
*[precision[..., i1, i2] for k2, i2 in slices if k2 in b])
for k1, i1 in slices if k1 in a
])
prec_bb = ops.cat(
-2, *[
ops.cat(
-1,
*[precision[..., i1, i2] for k2, i2 in slices if k2 in b])
for k1, i1 in slices if k1 in b
])
info_a = ops.cat(-1, *[info_vec[..., i] for k, i in slices if k in a])
info_b = ops.cat(-1, *[info_vec[..., i] for k, i in slices if k in b])
value_b = ops.cat(-1, *[values[k] for k, i in slices if k in b])
info_vec = info_a - _mv(prec_ab, value_b)
log_scale = _vv(value_b, info_b - 0.5 * _mv(prec_bb, value_b))
precision = ops.expand(prec_aa, info_vec.shape + info_vec.shape[-1:])
inputs = int_inputs.copy()
for k, d in self.inputs.items():
if k not in subs:
inputs[k] = d
result = Gaussian(info_vec, precision, inputs) + Tensor(
log_scale, int_inputs)
return Subs(result, remaining_subs) if remaining_subs else result
