Source code for surrogate.mutation.mutUniformInt
# Copyright 2016 Quan Pan
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
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# Author: Quan Pan <quanpan302@hotmail.com>
# License: Apache License, Version 2.0
# Create: 2016-12-02
import random
from collections import Sequence
from itertools import repeat
[docs]def mutUniformInt(variable, low=0.0, up=1.0, prob=0.5):
"""Mutate an individual by replacing attributes, with probability *prob*,
by a integer uniformly drawn between *low* and *up* inclusively.
:param variable: :term:`Sequence <sequence>` Decision Variable to be mutated.
:param low: The lower bound or a :term:`python:sequence` of
of lower bounds of the range from wich to draw the new
integer.
:param up: The upper bound or a :term:`python:sequence` of
of upper bounds of the range from wich to draw the new
integer.
:param prob: Independent probability for each attribute to be mutated.
:returns: A tuple of one variable.
"""
size = len(variable)
# size = variable.size
if not isinstance(low, Sequence):
low = repeat(low, size)
elif len(low) < size:
raise IndexError("low must be at least the size of variable: %d < %d" % (len(low), size))
if not isinstance(up, Sequence):
up = repeat(up, size)
elif len(up) < size:
raise IndexError("up must be at least the size of variable: %d < %d" % (len(up), size))
for i, xl, xu in zip(xrange(size), low, up):
if random.random() < prob:
variable[i] = random.randint(xl, xu)
return variable