https://github.com/GPflow/GPflow
Tip revision: 435a7ffac5a7188a6886aba9f43ebc87a1dde1df authored by Artem Artemev on 20 May 2020, 13:59:30 UTC
Merge pull request #1481 from GPflow/develop
Merge pull request #1481 from GPflow/develop
Tip revision: 435a7ff
bijectors.py
from typing import Optional
import tensorflow_probability as tfp
from .. import config
from .utilities import to_default_float
__all__ = ["positive", "triangular"]
def positive(lower: Optional[float] = None, base: Optional[str] = None) -> tfp.bijectors.Bijector:
"""
Returns a positive bijector (a reversible transformation from real to positive numbers).
:param lower: overrides default lower bound
(if None, defaults to gpflow.config.default_positive_minimum())
:param base: overrides base positive bijector
(if None, defaults to gpflow.config.default_positive_bijector())
:returns: a bijector instance
"""
bijector = base if base is not None else config.default_positive_bijector()
bijector = config.positive_bijector_type_map()[bijector.lower()]()
lower_bound = lower if lower is not None else config.default_positive_minimum()
if lower_bound != 0.0:
shift = tfp.bijectors.Shift(to_default_float(lower_bound))
bijector = tfp.bijectors.Chain([shift, bijector]) # from unconstrained to constrained
return bijector
def triangular() -> tfp.bijectors.Bijector:
"""
Returns instance of a triangular bijector.
"""
return tfp.bijectors.FillTriangular()