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Prior = class Prior(builtins.object) |
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Prior(limits=None, circular=False, domain=[-inf, inf], prior=None)
Base class defining prior distributions.
Two methods need to be defined in specific priors which map
the values between [0,1] on to the domain, and vice versa:
unit2Domain and domain2Unit.
u = domain2Unit( d )
d = unit2Domain( u )
d is a value in the domain of the prior and u is a vlue in [0,1]
The handling of limits is relegated to this Prior class. Define
_umin = domain2Unit( lowLimit )
_urng = domain2Unit( highLimit ) - umin
u = ( domain2Unit( d ) - umin ) / urange
d = unit2Domain( u * urange + umin )
Symmetric priors can be used in a circular variant; i.e.
the low and high limits are folded on each other, provided
that the limit values are the same (hence symmetric)
u = limitedDomain2Unit( d ) + 1 ) / 3
d = limitedUnit2Domain( ( u * 3 ) % 1 )
The copy method is also necessary.
Attributes
----------
lowLimit : float
low limit on the Prior
highLimit : float
high limit on the Prior
deltaP : float
width of numerical partial derivative calculation
circular : bool or float
whether circular
Hidden Attributes
-----------------
_lowDomain : float
lower limit of the Priors possible values
_highDomain : float
upper limit of the Priors possible values
_umin : float
umin lowLimit in unit
_urng : float
urange (hi-lo) in unit
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Constructor:
- Prior( limits=None, circular=False, domain=[-inf, inf], prior=None )
- Default constructor.
Parameters
----------
limits : None or list of 2 floats
2 limits resp. low and high
circular : bool or float
False not circular
True circular with period from limits[0] to limits[1]
period of circularity
domain : 2 floats
over which the prior is defined
prior : Prior
prior to copy (with new limits if applicable)
Methods defined here:
- checkLimit( par )
- Check whether the parameter is within limits.
Parameters
----------
par : float
the parameter to check
Raises
------
ValueError when outside limits.
- circularDomain2Unit( dval )
- circularUnit2Domain( uval )
- copy()
- Return a copy
- domain2Unit( dval )
- Return a value in [0,1] given a value within the valid domain of
a parameter for a distribution.
Parameters
----------
dval : float
value within the domain of a parameter
- getIntegral()
- Return the integral of the prior over the valid range.
Default: 1.0 (for bound priors)
- getLimits()
- Return the limits.
- getRange()
- Return the range.
- hasHighLimit()
- Return true if the prior has its high limits set.
- hasLimits()
- Return true if it has any limits.
- hasLowLimit()
- Return true if the prior has its low limits set.
- isBound()
- Return true if the integral over the prior is bound.
- isCircular()
- Whether circular
- isOutOfLimits( par )
- True if the parameter is out of limits
Parameters
----------
par : float
the parameter to check
- limitedDomain2Unit( dval )
- Shrink domain to value in [0,1]
- limitedUnit2Domain( uval )
- Expand value in [0,1] to domain
- logResult( p )
- Return the log of the result; -inf when p == 0.
Parameters
----------
p : float
the value
- numPartialDomain2Unit( dval )
- Return a the numeric derivate of the domain2Unit function to dval.
Parameters
----------
dval : float
value within the domain of a parameter
- numPartialLog( p )
- Return the numeric partial derivative of log( Prior ) wrt parameter.
Parameters
----------
p : float
the value
- partialDomain2Unit( p )
- Return the derivative of Domain2Unit, aka the result of the distribution at p
Parameters
----------
p : float
the value
- partialLog( p )
- Return partial derivative of log( Prior ) wrt parameter.
default numPartialLog
Parameters
----------
p : float
the value
- result( p )
- Return value of the Prior at a given value.
If result is not defined, fall back to numerical derivative od Domain2Unit.
Parameters
----------
p : float
the value
- setAttributes( limits=None, scale=None )
- Set possible attributes for a Prior.
Parameters
----------
limits : float or None
[low,high] limit
scale : float or None
scale factor
- setLimits( limits=None )
- Set limits.
It is asserted that lowLimit is smaller than highLimit.
Parameters
----------
limits : None or list of any combination of [None, float]
None : no limit (for both or one)
float : [low,high] limit
Raises
------
ValueError when low limit is larger than high limit or out of Domain
- setPriorAttributes( limits, circular )
- stayInLimits( par )
- Return lower limit or upper limit when parameter is outside.
Parameters
----------
par : float
the parameter to check
- unit2Domain( uval )
- Return a value within the valid domain of the parameter given a value
between [0,1] for a distribution.
Parameters
----------
uval : float
value within [0,1]
- unsetLimits()
- Remove all limits.
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