expression_weighted (dCGP-W)

weighted dCGP expression

Three types of expression_weighted are currently available in python. They differ from the type they operate upon: double, gdual, vectorized gdual.

expression_weighted_double

class dcgpy.expression_weighted_double(inputs, outputs, rows, cols, levels_back, arity = 2, kernels, n_eph = 0, seed = randint)

A weighted CGP expression

Constructs a CGP expression operating on double

Parameters

  • inputs (int) – number of inputs

  • outputs (int) – number of outputs

  • rows (int) – number of rows of the cartesian representation of the expression as an acyclic graph.

  • cols (int) – number of columns of the cartesian representation of the expression as an acyclic graph.

  • levels_back (int) – number of levels-back allowed. This, essentially, controls the minimum number of allowed operations in the formula. If uncertain set it to cols + 1

  • arity (int on list) – arity of the kernels. Assumed equal for all columns unless its specified by a list. The list must contain a number of entries equal to the number of columns.

  • kernels (List[dcgpy.kernel_double]) – kernel functions

  • n_eph (int) – Number of ephemeral constants. Their values and their symbols can be set via dedicated methods.

  • seed (int) – random seed to generate mutations and chromosomes

eph_val

Values of the ephemeral constants.

Type

list(`)double`

eph_symb

Symbols used for the ephemeral constants.

Type

list(str)

Examples:

>>> from dcgpy import *
>>> dcgp = expression_double(1,1,1,10,11,2,kernel_set_double(["sum","diff","mul","div"])(), 0, 32)
>>> print(dcgp)
...
>>> num_out = dcgp([in])
>>> sym_out = dcgp(["x"])
get_weight(node_id, input_id)

Gets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

Returns

The value of the weight (a float)

Raises

ValueError – if node_id or input_id are not valid

get_weights()

Gets all weights

set_weight(node_id, input_id, weight)

Sets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node whose weight is being set

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

  • weight (float) – the new value of the weight

Raises

ValueError – if node_id or input_id are not valid

set_weights(weights)

Sets all weights.

Parameters

weights (List[float]) – the new values of the weights

Raises

ValueError – if the input vector dimension is not valid (r*c*arity)

expression_weighted_gdual_double

class dcgpy.expression_weighted_gdual_double(inputs, outputs, rows, cols, levels_back, arity = 2, kernels, n_eph = 0, seed = randint)

A weighted CGP expression

Constructs a CGP expression operating on gdual_double

Parameters

  • inputs (int) – number of inputs

  • outputs (int) – number of outputs

  • rows (int) – number of rows of the cartesian representation of the expression as an acyclic graph.

  • cols (int) – number of columns of the cartesian representation of the expression as an acyclic graph.

  • levels_back (int) – number of levels-back allowed. This, essentially, controls the minimum number of allowed operations in the formula. If uncertain set it to cols + 1

  • arity (int on list) – arity of the kernels. Assumed equal for all columns unless its specified by a list. The list must contain a number of entries equal to the number of columns.

  • kernels (List[dcgpy.kernel_gdual_double]) – kernel functions

  • n_eph (int) – Number of ephemeral constants. Their values and their symbols can be set via dedicated methods.

  • seed (int) – random seed to generate mutations and chromosomes

eph_val

Values of the ephemeral constants.

Type

list(`)gdual_double`

eph_symb

Symbols used for the ephemeral constants.

Type

list(str)

Examples:

>>> from dcgpy import *
>>> dcgp = expression_gdual_double(1,1,1,10,11,2,kernel_set_gdual_double(["sum","diff","mul","div"])(), 0, 32)
>>> print(dcgp)
...
>>> num_out = dcgp([in])
>>> sym_out = dcgp(["x"])
get_weight(node_id, input_id)

Gets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

Returns

The value of the weight (a float)

Raises

ValueError – if node_id or input_id are not valid

get_weights()

Gets all weights

set_weight(node_id, input_id, weight)

Sets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node whose weight is being set

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

  • weight (float) – the new value of the weight

Raises

ValueError – if node_id or input_id are not valid

set_weights(weights)

Sets all weights.

Parameters

weights (List[float]) – the new values of the weights

Raises

ValueError – if the input vector dimension is not valid (r*c*arity)

expression_weighted_gdual_vdouble

class dcgpy.expression_weighted_gdual_vdouble(inputs, outputs, rows, cols, levels_back, arity = 2, kernels, n_eph = 0, seed = randint)

A weighted CGP expression

Constructs a CGP expression operating on gdual_vdouble

Parameters

  • inputs (int) – number of inputs

  • outputs (int) – number of outputs

  • rows (int) – number of rows of the cartesian representation of the expression as an acyclic graph.

  • cols (int) – number of columns of the cartesian representation of the expression as an acyclic graph.

  • levels_back (int) – number of levels-back allowed. This, essentially, controls the minimum number of allowed operations in the formula. If uncertain set it to cols + 1

  • arity (int on list) – arity of the kernels. Assumed equal for all columns unless its specified by a list. The list must contain a number of entries equal to the number of columns.

  • kernels (List[dcgpy.kernel_gdual_vdouble]) – kernel functions

  • n_eph (int) – Number of ephemeral constants. Their values and their symbols can be set via dedicated methods.

  • seed (int) – random seed to generate mutations and chromosomes

eph_val

Values of the ephemeral constants.

Type

list(`)gdual_vdouble`

eph_symb

Symbols used for the ephemeral constants.

Type

list(str)

Examples:

>>> from dcgpy import *
>>> dcgp = expression_gdual_vdouble(1,1,1,10,11,2,kernel_set_gdual_vdouble(["sum","diff","mul","div"])(), 0, 32)
>>> print(dcgp)
...
>>> num_out = dcgp([in])
>>> sym_out = dcgp(["x"])
get_weight(node_id, input_id)

Gets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

Returns

The value of the weight (a float)

Raises

ValueError – if node_id or input_id are not valid

get_weights()

Gets all weights

set_weight(node_id, input_id, weight)

Sets a weight.

Note

Convention adopted for node numbering: http://ppsn2014.ijs.si/files/slides/ppsn2014-tutorial3-miller.pdf

Parameters

  • node_id (int) – the id of the node whose weight is being set

  • input_id (int) – the id of the node input (0 for the first one up to arity-1)

  • weight (float) – the new value of the weight

Raises

ValueError – if node_id or input_id are not valid

set_weights(weights)

Sets all weights.

Parameters

weights (List[float]) – the new values of the weights

Raises

ValueError – if the input vector dimension is not valid (r*c*arity)