HyperGP.PrimitiveSet Module

class PrimitiveSet

PrimitiveSet module is used to collects the primitives and terminals used in GP evolution

To use the PrimitiveSet, we should firstly import it from HyperGP and initilize it:

>>> from HyperGP import PrimitiveSet

Methods

__init__(input_arity[, primitive_set, prefix])
registerPrimitive(name, func, arity[, states])	We can also register function after the PrimitiveSet module has been initialized.
registerTerminal([name])	Except for the auto generated terminals, we can also register terminals after the PrimitiveSet module has been initialized.
registerEphemeralTerminal(name, func[, ...])	Used to generate the terminal with functions
genFunc(name)	Search the register function with its name
genTerminal(name)	Search the register terminal with its name
select()	randomly select from the primitive set
selectFunc()	randomly select a function from the primitive set
selectTerminal()	randomly select a terminal from the primitive set
copy()	A deep copy of the primitive set

Attributes

primitiveSet	Get a name list of the register functions
terminalSet	Get a name list of the terminals

__init__(input_arity, primitive_set=None, prefix='x')

Parameters:

• input_arity (int) – the number of terminals.

• primitive_set (list) – a list with the format [(name, func, arity, states), ..]. for each prim, a tuple with name, function, arity is needed. To make the framework more flexible, it is also supported to register the states with States module for each prim, just add it behind the three element in each tuple. The detailed examples will be provided below.

• prefix (str) – determine the name used for input terminals. The pre-defined str is ‘x’, then the terminals will be printed like ‘x1’, ‘x2’, … .

Examples

Initialize the PrimitiveSet

>>> pset = PrimitiveSet(
>>> input_arity=1,
>>> primitive_set=[
>>>     ('add', HyperGP.tensor.add, 2),
>>>     ('sub', HyperGP.tensor.sub, 2),
>>>     ('mul', HyperGP.tensor.mul, 2),
>>>     ('div', HyperGP.tensor.div, 2),
>>> ])

For each prim, we can also register additional states. For example, when we apply HyperGP to image classification:

>>> pset = PrimitiveSet(
>>> input_arity=1,
>>> primitive_set=[
    ("gau_filter", HyperGP.gauss_filter, 3, States(type="filter"))
>>> ])
>>> print(pset.genFunc("gau_filter").type)
filter

copy()

A deep copy of the primitive set

Returns:

A new PrimitiveSet

genFunc(name)

Search the register function with its name

Parameters:

name (str) – the function name want to search

Returns:

The callable register function

Examples

>>> pset = PrimitiveSet(
>>> input_arity=5,
>>> primitive_set=[
>>>     ('add', HyperGP.tensor.add, 2),
>>>     ('sub', HyperGP.tensor.sub, 2),
>>> ])
>>> prim = pset.genFunc('add')
>>> print(prim, type(prim))
add, <class 'HyperGP.base.func_basic.Func'>

genTerminal(name)

Search the register terminal with its name

Parameters:

name (str) – the terminal name want to search

Returns:

The register terminal.

Note

If it is a callable ephemeral constant, then the generated term is a Constant module with the return value of the function.

Examples

>>> pset = PrimitiveSet(
>>> input_arity=5,
>>> primitive_set=[
>>>     ('add', HyperGP.tensor.add, 2),
>>>     ('sub', HyperGP.tensor.sub, 2),
>>> ])
>>> term = pset.genTerminal('x0')
>>> print(term, type(term))
x0, <class 'HyperGP.base.func_basic.Terminal'>

max_arity()

Statistics the max arity of the registered function

Returns:

A new PrimitiveSet

property primitiveSet

Get a name list of the register functions

Returns:

The name list of the register functions

Examples

>>> pset = PrimitiveSet(
>>> input_arity=1,
>>> primitive_set=[
>>>     ('add', HyperGP.tensor.add, 2),
>>>     ('sub', HyperGP.tensor.sub, 2),
>>> ])
>>> print(pset.primitiveSet)
['add', 'sub']

registerEphemeralTerminal(name, func, ephemeral=True, **kwargs)

Used to generate the terminal with functions

Parameters:

• name (str) – a sign of the terminal. It is used to search the register terminal, with genTerminal function.

• function (function-like) – The function called when get it from the PrimitiveSet module

Examples

>>> pset = PrimitiveSet(
>>>     input_arity=2
>>> )
>>> def constants():
... return random.uniform(0, 1)
>>> pset.registerEphemeralTerminal("y", constants)
>>> term = pset.genTerminal("y")
>>> print(term, type(term))
0.9997361496151884 <class 'HyperGP.base.func_basic.Constant'>

registerPrimitive(name, func, arity, states=None, **kwargs)

We can also register function after the PrimitiveSet module has been initialized.

Parameters:

• name (str) – a sign of the function, which will be shown when print the function. It is also used to search the register function, with genFunc function.

• func (function-like) – the function want to register.

• arity (int) – the arity of the register function.

• states (HyperGP.States) – the states want to register in the function, using HyperGP.States module.

• kwargs – The input kwargs for each prim will be used as default parameters whenever the prim is called.

Examples

>>> pset = PrimitiveSet(
>>>     input_arity=1
>>> )
>>>
>>> param_types_1 = ["img", "mask", "channel"]
>>> param_types_2 = ["img", "channel"]
>>> param_types_3 = ["img", "w_h", "region"]
>>>
>>> pset.registerPrimitive("gau_filter", HyperGP.gauss_filter, 3, states=States(type="filter", param=param_types_1), padding=(1, 1))
>>> pset.registerPrimitive("sobel_filter", HyperGP.sobel_filter, 2, states=States(type="filter", param=param_types_2), padding=(1, 1))
>>> pset.registerPrimitive("mean_filter", HyperGP.mean_filter, 3, states=States(param=param_types_1, type="filter"), padding=(1, 1))
>>> pset.registerPrimitive("mean", s_mean, 1, states=States(param=["img"], type="norm"))
>>> pset.registerPrimitive("region_detect", region_detect, 3, states=States(param=param_types_3, type="region"))

registerTerminal(name=None, **kwargs)

Except for the auto generated terminals, we can also register terminals after the PrimitiveSet module has been initialized.

Parameters:

• name (str) – a sign of the terminal, which will be shown when print it. It is also used to search the register terminal, with genTerminal function.

• kwargs – will be registered to the attrs of the terminal.

Examples

>>> pset = PrimitiveSet(
>>>     input_arity=2
>>> )
>>>
>>> pset.registerTerminal("y")
>>> print(pset.terminalSet)
['x0', 'x1', 'y']
>>> pset.registerTerminal()
>>> print(pset.terminalSet)
['x0', 'x1', 'y', 'x2']

select()

randomly select from the primitive set

Returns:

a Func, Terminal or Constant module

Examples

>>> prim = pset.select()
>>> print(prim, type(prim))
div, <class 'HyperGP.base.func_basic.Func'>

selectFunc()

randomly select a function from the primitive set

Returns:

a Func module

Examples

>>> prim = pset.selectFunc()
>>> print(prim, type(prim))
add, <class 'HyperGP.base.func_basic.Func'>

selectTerminal()

randomly select a terminal from the primitive set

Returns:

a Terminal or Constant module

Examples

>>> term = pset.selectTerminal()
>>> print(term, type(term))
x0, <class 'HyperGP.base.func_basic.Terminal'>

property terminalSet

Get a name list of the terminals

Returns:

The name list of the register terminals

Examples

>>> pset = PrimitiveSet(
>>> input_arity=5,
>>> primitive_set=[
>>>     ('add', HyperGP.tensor.add, 2),
>>>     ('sub', HyperGP.tensor.sub, 2),
>>> ])
>>> print(pset.terminalSet)
['x0', 'x1', 'x2', 'x3', 'x4']