Parameter

class sherpa.models.parameter.Parameter(modelname: str, name: str, val: SupportsFloat, min: SupportsFloat = -3.4028234663852886e+38, max: SupportsFloat = 3.4028234663852886e+38, hard_min: SupportsFloat = -3.4028234663852886e+38, hard_max: SupportsFloat = 3.4028234663852886e+38, units: str = '', frozen: bool = False, alwaysfrozen: bool = False, hidden: bool = False, aliases: Sequence[str] | None = None)[source] [edit on github]

Bases: NoNewAttributesAfterInit

Represent a model parameter.

Parameters:
modelnamestr

The name of the model component containing the parameter.

namestr

The name of the parameter. It should be considered to be matched in a case-insensitive manner.

valnumber

The default value for the parameter.

min, max, hard_min, hard_max: number, optional

The soft and hard limits for the parameter value.

unitsstr, optional

The units for the parameter value.

frozenbool, optional

Does the parameter default to being frozen?

alwaysfrozenbool, optional

If set then the parameter can never be thawed.

hiddenbool, optional

Should the parameter be included when displaying the model contents?

aliasesNone or list of str

If not None then alternative names for the parameter (these are expected to be matched in a case-insensitive manner).

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

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 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

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

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

freeze() → None[source] [edit on github]

Set the frozen attribute for the parameter.

See also

frozen, thaw
reset() → None[source] [edit on github]

Reset the parameter value and limits to their default values.

set(val: SupportsFloat | None = None, min: SupportsFloat | None = None, max: SupportsFloat | None = None, frozen: bool | None = None, default_val: SupportsFloat | None = None, default_min: SupportsFloat | None = None, default_max: SupportsFloat | None = None) → None[source] [edit on github]

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[source] [edit on github]

Unset the frozen attribute for the parameter.

Raises:
ParameterErr

The parameter is marked as always frozen.

See also

freeze, frozen

Remove any link to other parameters.