Source code for Individual.BitstreamIndividual

 1"""Individual representation for evolutionary bitstream experiments.
 2
 3Each individual wraps a boolean bitstream that maps to an FPGA circuit
 4configuration. Provides mutation, crossover, and randomization operators
 5used by the population initialization and reproduction strategies.
 6"""
 7
 8from random import Random
 9
10

[docs]
11class BitstreamIndividual:
12    """A genetic individual whose genome is a list of boolean bits.
13
14    Used by :class:`~Population.PopulationInitialization.GenerateBitstreamPopulation`
15    to create populations, and by reproducers to generate offspring.
16    """

[docs]
17    def __init__(self, bitstream_sz: int, rand: Random, mutation_probability: float):
18        """Create an individual with a zeroed bitstream of the given size."""
19        self.__bitstream: list[bool] = [False] * bitstream_sz
20        self.__rand = rand
21        self.__mutation_probability = mutation_probability

22

[docs]
23    def set_bitstream(self, bitstream: list[bool]):
24        """Replace the entire bitstream with the provided list."""
25        self.__bitstream = bitstream

26

[docs]
27    def get_bitstream(self) -> list[bool]:
28        """Return the current bitstream."""
29        return self.__bitstream

30

[docs]
31    def mutate(self):
32        """Flip each bit independently with the configured mutation probability."""
33        for i in range(len(self.__bitstream)):
34            if self.__mutation_probability >= self.__rand.uniform(0,1):
35                self.__bitstream[i] = not self.__bitstream[i]

36

[docs]
37    def crossover(self, parent: 'BitstreamIndividual', crossover_point: int):
38        """Single-point crossover: take bits before *crossover_point* from self and the rest from *parent*."""
39        first = self.__bitstream[0:crossover_point]
40        second = parent.__bitstream[crossover_point:]
41        new_bitstream = first + second
42        self.set_bitstream(new_bitstream)

43

[docs]
44    def randomize(self):
45        """Set every bit to a uniformly random value."""
46        for i in range(len(self.__bitstream)):
47            if self.__rand.randint(0, 1) == 0:
48                self.__bitstream[i] = False
49            else:
50                self.__bitstream[i] = True

51

[docs]
52    def copy_from(self, other: 'BitstreamIndividual'):
53        """Deep-copy the bitstream from *other* into this individual."""
54        self.__bitstream = other.__bitstream.copy()


55