CompositeParameter

class sherpa.models.parameter.CompositeParameter(name: str, parts: Sequence[Parameter])[source] [edit on github]

Bases: Parameter

Represent a parameter with composite parts.

This is the base class for representing expressions that combine multiple parameters and values.

Parameters:

namestr: The name for the collection.
partssequence of Parameter objects: The parameters.

Attributes:

alwaysfrozen: Is the parameter always frozen?
default_max
default_min
default_val: The default value of the parameter.
frozen: Is the parameter currently frozen?
hard_max: The hard maximum of the parameter.
hard_min: The hard minimum of the parameter.
link: The link expression to other parameters, if set.
max: The maximum value of the parameter.
min: The minimum value of the parameter.
val: The current value of the parameter.

Methods

`eval`()	Evaluate the composite expression.
`freeze`()	Set the `frozen` attribute for the parameter.
`reset`()	Reset the parameter value and limits to their default values.
`set`([val, min, max, frozen, default_val, ...])	Change a parameter setting.
`thaw`()	Unset the `frozen` attribute for the parameter.
`unlink`()	Remove any link to other parameters.

Notes

Composite parameters can be iterated through to find their components:

>>> p = Parameter('m', 'p', 2)
>>> q = Parameter('m', 'q', 4)
>>> c = (p + q) / 2
>>> c
<BinaryOpParameter '(m.p + m.q) / 2'>
>>> for cpt in c:
...     print(type(cpt))
...
<class 'sherpa.models.parameter.BinaryOpParameter'>
<class 'sherpa.models.parameter.Parameter'>
<class 'sherpa.models.parameter.Parameter'>
<class 'sherpa.models.parameter.ConstantParameter'>

Attributes Summary

`alwaysfrozen`	Is the parameter always frozen?
`default_max`
`default_min`
`default_val`	The default value of the parameter.
`frozen`	Is the parameter currently frozen?
`hard_max`	The hard maximum of the parameter.
`hard_min`	The hard minimum of the parameter.
`link`	The link expression to other parameters, if set.
`max`	The maximum value of the parameter.
`min`	The minimum value of the parameter.
`numpy_binop_with_symbols`
`val`	The current value of the parameter.

Methods Summary

`eval`()	Evaluate the composite expression.
`freeze`()	Set the `frozen` attribute for the parameter.
`reset`()	Reset the parameter value and limits to their default values.
`set`([val, min, max, frozen, default_val, ...])	Change a parameter setting.
`thaw`()	Unset the `frozen` attribute for the parameter.
`unlink`()	Remove any link to other parameters.

Attributes Documentation

alwaysfrozen: Is the parameter always frozen?

default_max

default_min

default_val

The default value of the parameter.

See also

val

frozen

Is the parameter currently frozen?

Those parameters created with alwaysfrozen set can not be changed.

See also

alwaysfrozen

hard_max

The hard maximum of the parameter.

See also

hard_min

hard_min

The hard minimum of the parameter.

See also

hard_max

link

The link expression to other parameters, if set.

The link expression defines if the parameter is not a free parameter but is actually defined in terms of other parameters.

See also

val

Examples

>>> a = Parameter("mdl", "a", 2)
>>> b = Parameter("mdl", "b", 1)
>>> b.link = 10 - a
>>> print(a.val)
2.0
>>> print(b.val)
8.0

max

The maximum value of the parameter.

The maximum must lie between the hard_min and hard_max limits.

See also

min, val

min

The minimum value of the parameter.

The minimum must lie between the hard_min and hard_max limits.

See also

max, val

numpy_binop_with_symbols = {<ufunc 'add'>: '+', <ufunc 'divide'>: '/', <ufunc 'floor_divide'>: '//', <ufunc 'multiply'>: '*', <ufunc 'power'>: '**', <ufunc 'remainder'>: '%', <ufunc 'subtract'>: '-'}

val

The current value of the parameter.

If the parameter is a link then it is possible that accessing the value will raise a ParameterErr in cases where the link expression falls outside the soft limits of the parameter.

See also

default_val, link, max, min

Methods Documentation

eval() → SupportsFloat[source] [edit on github]: Evaluate the composite expression.

freeze() → None [edit on github]

Set the frozen attribute for the parameter.

See also

frozen, thaw

reset() → None [edit on github]: Reset the parameter value and limits to their default values.

Change a parameter setting.

Parameters:

valnumber or None, optional: The new parameter value.
min, maxnumber or None, optional: The new parameter range.
frozenbool or None, optional: Should the frozen flag be set?
default_valnumber or None, optional: The new default parameter value.
default_min, default_maxnumber or None, optional: The new default parameter limits.

thaw() → None [edit on github]

Unset the frozen attribute for the parameter.

Raises:

ParameterErr: The parameter is marked as always frozen.

See also

freeze, frozen

unlink() → None [edit on github]: Remove any link to other parameters.