Util – utility module

This is the utility module, with some utility functions of general use, like list item swap, random utilities and etc.

class Util.ErrorAccumulator

An accumulator for the Root Mean Square Error (RMSE) and the Mean Square Error (MSE)

append(target, evaluated)

Add value to the accumulator

Parameters:

• target – the target value
• evaluated – the evaluated value

getAdjusted()

Returns the adjusted fitness This fitness is calculated as 1 / (1 + standardized fitness)

getMSE()

Return the mean square error

Return type:float MSE

getMean()

Return the mean of the non-squared accumulator

getNonSquared()

Returns the non-squared accumulator

getRMSE()

Return the root mean square error

Return type:float RMSE

getSquared()

Returns the squared accumulator

reset()

Reset the accumulator

Util.G1DListGetEdges(individual)

Get the edges of a G1DList individual

Parameter:individual – the G1DList individual Return type:the edges dictionary

Util.G1DListGetEdgesComposite(mom, dad)

Get the edges and the merge between the edges of two G1DList individuals

Parameters:

• mom – the mom G1DList individual
• dad – the dad G1DList individual

Return type:

a tuple (mom edges, dad edges, merge)

Util.G1DListMergeEdges(eda, edb)

Get the merge between the two individual edges

Parameters:

• eda – the edges of the first G1DList genome
• edb – the edges of the second G1DList genome

Return type:

the merged dictionary

class Util.Graph

The Graph class

Example:

>>> g = Graph()
>>> g.addEdge("a", "b")
>>> g.addEdge("b", "c")
>>> for node in g:
...    print node
a
b
c

New in version 0.6: The Graph class.

addEdge(a, b)

Add an edge between two nodes, if the nodes doesn’t exists, they will be created

Parameters:

• a – the first node
• b – the second node

addNode(node)

Add the node

Parameter:node – the node to add

getNeighbors(node)

Returns the neighbors of the node

Parameter:node – the node

getNodes()

Returns all the current nodes on the graph

Return type:the list of nodes

reset()

Deletes all nodes of the graph

Util.cmp_individual_raw(a, b)

Compares two individual raw scores

Example:

>>> GPopulation.cmp_individual_raw(a, b)

Parameters:

• a – the A individual instance
• b – the B individual instance

Return type:

0 if the two individuals raw score are the same, -1 if the B individual raw score is greater than A and 1 if the A individual raw score is greater than B.

Note

this function is used to sorte the population individuals

Util.cmp_individual_scaled(a, b)

Compares two individual fitness scores, used for sorting population

Example:

>>> GPopulation.cmp_individual_scaled(a, b)

Parameters:

• a – the A individual instance
• b – the B individual instance

Return type:

0 if the two individuals fitness score are the same, -1 if the B individual fitness score is greater than A and 1 if the A individual fitness score is greater than B.

Note

this function is used to sorte the population individuals

Util.importSpecial(name)

This function will import the name module, if fails, it will raise an ImportError exception and a message

Parameter:name – the module name Return type:the module object

New in version 0.6: The import_special function

Util.list2DSwapElement(lst, indexa, indexb)

Swaps elements A and B in a 2D list (matrix).

Example:

>>> l = [ [1,2,3], [4,5,6] ] 
>>> Util.list2DSwapElement(l, (0,1), (1,1) )
>>> l
[[1, 5, 3], [4, 2, 6]]

Parameters:

• lst – the list
• indexa – the swap element A
• indexb – the swap element B

Return type:

None

Util.listSwapElement(lst, indexa, indexb)

Swaps elements A and B in a list.

Example:

>>> l = [1, 2, 3]
>>> Util.listSwapElement(l, 1, 2)
>>> l
[1, 3, 2]

Parameters:

• lst – the list
• indexa – the swap element A
• indexb – the swap element B

Return type:

None

Util.raiseException(message, expt=None)

Raise an exception and logs the message.

Example:

>>> Util.raiseException('The value is not an integer', ValueError)

Parameters:

• message – the message of exception
• expt – the exception class

Return type:

None

Util.rand_random()

random() -> x in the interval [0, 1).

Util.randomFlipCoin(p)

Returns True with the p probability. If the p is 1.0, the function will always return True, or if is 0.0, the function will return always False.

Example:

>>> Util.randomFlipCoin(1.0)
True

Parameter:p – probability, between 0.0 and 1.0 Return type:True or False