def _transform_to_interval(constraint):
# Handle the special case of the unit interval.
lower_is_0 = isinstance(constraint.lower_bound, numbers.Number) and constraint.lower_bound == 0
upper_is_1 = isinstance(constraint.upper_bound, numbers.Number) and constraint.upper_bound == 1
if lower_is_0 and upper_is_1:
return transforms.SigmoidTransform()
loc = constraint.lower_bound
scale = constraint.upper_bound - constraint.lower_bound
return transforms.ComposeTransform([transforms.SigmoidTransform(),
transforms.AffineTransform(loc, scale)])
def _transform_to_interval(constraint):
loc = constraint.lower_bound
scale = constraint.upper_bound - constraint.lower_bound
return transforms.ComposeTransform([
transforms.SigmoidTransform(),
transforms.AffineTransform(loc, scale)
])
return transforms.ComposeTransform(
[transforms.ExpTransform(),
transforms.AffineTransform(loc, scale)])
@biject_to.register(constraints.less_than)
@transform_to.register(constraints.less_than)
def _transform_to_less_than(constraint):
loc = constraint.upper_bound
scale = loc.new([-1]).expand_as(loc)
return transforms.ComposeTransform(
[transforms.ExpTransform(),
transforms.AffineTransform(loc, scale)])
biject_to.register(constraints.unit_interval, transforms.SigmoidTransform())
transform_to.register(constraints.unit_interval, transforms.SigmoidTransform())
@biject_to.register(constraints.interval)
@transform_to.register(constraints.interval)
def _transform_to_interval(constraint):
loc = constraint.lower_bound
scale = constraint.upper_bound - constraint.lower_bound
return transforms.ComposeTransform([
transforms.SigmoidTransform(),
transforms.AffineTransform(loc, scale)
])
biject_to.register(constraints.simplex, transforms.StickBreakingTransform())
def TanhTransform():
return transforms.ComposeTransform([
transforms.AffineTransform(loc=0., scale=2.),
transforms.SigmoidTransform(),
transforms.AffineTransform(loc=-1., scale=2.)
])
