def test_zeros():
"""Tests zeros"""
# Scalar
zeros = ops.zeros([1])
assert isinstance(zeros, tf.Tensor)
assert zeros.ndim == 1
assert zeros.shape[0] == 1
assert zeros.numpy() == 0.0
# 1D
zeros = ops.zeros([5])
assert isinstance(zeros, tf.Tensor)
assert zeros.ndim == 1
assert zeros.shape[0] == 5
assert all(zeros.numpy() == 0.0)
# 2D
zeros = ops.zeros([5, 4])
assert isinstance(zeros, tf.Tensor)
assert zeros.ndim == 2
assert zeros.shape[0] == 5
assert zeros.shape[1] == 4
assert np.all(zeros.numpy() == 0.0)
# 3D
zeros = ops.zeros([5, 4, 3])
assert isinstance(zeros, tf.Tensor)
assert zeros.ndim == 3
assert zeros.shape[0] == 5
assert zeros.shape[1] == 4
assert zeros.shape[2] == 3
assert np.all(zeros.numpy() == 0.0)
def kl_loss(self):
"""Compute the sum of the Kullback–Leibler divergences between this
parameter's priors and its variational posteriors."""
if self.prior is None:
return O.zeros([])
else:
return O.sum(O.kl_divergence(self.posterior, self.prior),
axis=None)
def __init__(self,
d: int = 1,
prior=None,
expand_dims: int = -1,
name='MultivariateNormalParameter'):
# Transformation for scale parameters
def log_cholesky_transform(x):
if get_backend() == 'pytorch':
raise NotImplementedError
else:
import tensorflow as tf
import tensorflow_probability as tfp
E = tfp.math.fill_triangular(x)
E = tf.linalg.set_diag(E,
tf.exp(tf.linalg.tensor_diag_part(E)))
return E @ tf.transpose(E)
# Prior
if prior is None:
prior = MultivariateNormal(O.zeros([d]), O.eye(d))
# Transform
if expand_dims is not None:
transform = lambda x: O.expand_dims(x, expand_dims)
else:
transform = None
# Initializer and variable transforms
initializer = {
'loc': lambda x: xavier([d]),
'cov': lambda x: xavier([int(d * (d + 1) / 2)])
}
var_transform = {'loc': None, 'cov': log_cholesky_transform}
super().__init__(posterior=MultivariateNormal,
prior=prior,
transform=transform,
initializer=initializer,
var_transform=var_transform,
name=name)
