matchzoo.engine.param

Parameter class.

Module Contents

Classes

Param

Parameter class.
matchzoo.engine.param.SpaceType
class matchzoo.engine.param.Param(name: str, value: typing.Any = None, hyper_space: typing.Optional[SpaceType] = None, validator: typing.Optional[typing.Callable[[typing.Any], bool]] = None, desc: typing.Optional[str] = None)

Bases: object

Parameter class.

Basic usages with a name and value:

>>> param = Param('my_param', 10)
>>> param.name
'my_param'
>>> param.value
10

Use with a validator to make sure the parameter always keeps a valid value.

>>> param = Param(
...     name='my_param',
...     value=5,
...     validator=lambda x: 0 < x < 20
... )
>>> param.validator  
<function <lambda> at 0x...>
>>> param.value
5
>>> param.value = 10
>>> param.value
10
>>> param.value = -1
Traceback (most recent call last):
    ...
ValueError: Validator not satifised.
The validator's definition is as follows:
validator=lambda x: 0 < x < 20

Use with a hyper space. Setting up a hyper space for a parameter makes the parameter tunable in a matchzoo.engine.Tuner.

>>> from matchzoo.engine.hyper_spaces import quniform
>>> param = Param(
...     name='positive_num',
...     value=1,
...     hyper_space=quniform(low=1, high=5)
... )
>>> param.hyper_space  
<matchzoo.engine.hyper_spaces.quniform object at ...>
>>> from hyperopt.pyll.stochastic import sample
>>> hyperopt_space = param.hyper_space.convert(param.name)
>>> samples = [sample(hyperopt_space) for _ in range(64)]
>>> set(samples) == {1, 2, 3, 4, 5}
True

The boolean value of a Param instance is only True when the value is not None. This is because some default falsy values like zero or an empty list are valid parameter values. In other words, the boolean value means to be “if the parameter value is filled”.

>>> param = Param('dropout')
>>> if param:
...     print('OK')
>>> param = Param('dropout', 0)
>>> if param:
...     print('OK')
OK

A _pre_assignment_hook is initialized as a data type convertor if the value is set as a number to keep data type consistency of the parameter. This conversion supports python built-in numbers, numpy numbers, and any number that inherits numbers.Number.

>>> param = Param('float_param', 0.5)
>>> param.value = 10
>>> param.value
10.0
>>> type(param.value)
<class 'float'>
property name(self) → str
Returns

Name of the parameter.

property value(self) → typing.Any
Returns

Value of the parameter.

property hyper_space(self) → SpaceType
Returns

Hyper space of the parameter.

property validator(self) → typing.Callable[[typing.Any], bool]
Returns

Validator of the parameter.

property desc(self) → str
Returns

Parameter description.

_infer_pre_assignment_hook(self)
_validate(self, value)
__bool__(self)
Returns

False when the value is None, True otherwise.

set_default(self, val, verbose=1)

Set default value, has no effect if already has a value.

Parameters

  • val – Default value to set.

  • verbose – Verbosity.

reset(self)

Set the parameter’s value to None, which means “not set”.

This method bypasses validator.

Example

>>> import matchzoo as mz
>>> param = mz.Param(
...     name='str', validator=lambda x: isinstance(x, str))
>>> param.value = 'hello'
>>> param.value = None
Traceback (most recent call last):
    ...
ValueError: Validator not satifised.
The validator's definition is as follows:
name='str', validator=lambda x: isinstance(x, str))
>>> param.reset()
>>> param.value is None
True