function breedNewPop($pop, $newPopSize, $ingredients)
{
$newPop = array();
foreach ($pop as $survivor) {
$newPop[] = $survivor;
$newPop[] = mutate($survivor, $ingredients);
}
if (count($newPop) < $newPopSize) {
$newPop = array_merge(generateInitialPopulation($ingredients, $newPopSize - count($newPop)), $newPop);
}
return $newPop;
}
<?php
$digit = 10;
$population_size = 100;
$generations = 100;
for ($i = 0; $i < $generations; $i++) {
$population = new_population($population_size);
$fitness = fitness($population);
$fitness = mutate($fitness);
echo "Fitness: " . $fitness . "<br>";
if ($fitness == 0) {
echo "Done at generation " . $i;
break;
}
}
//Creating population
function new_population($size)
{
$population = array();
for ($i = 0; $i < $size; $i++) {
$population[] = new Thing();
}
return $population;
}
//Computing fitness function
function fitness($population)
{
$best = 100;
for ($i = 0; $i < $population; $i++) {
$fitness = abs($population[$i]->digit - $digit);
if ($fitness < $best) {
function evolve(&$population)
{
$indexA = rand(0, count($population) - 1);
do {
$indexB = rand(0, count($population) - 1);
} while($indexB == $indexA);
$a = $population[$indexA];
$b = $population[$indexB];
printf("%d : %d\n", $indexA, $indexB);
$choose = chooseGenome($a, $b);
switch ($choose) {
case 1:
array_splice($population, $indexB, 1);
break;
case 2:
array_splice($population, $indexA, 1);
break;
}
if(count($population) == 2) {
printf("Merging.\n");
$cd = merge($population[0], $population[1]);
$population = array_merge($population, $cd);
}
if(rand(1,5) == 1) {
$index = rand(0, count($population) - 1);
printf("\t\t\tMutating %d\n", $index);
mutate($population[$index]);
}
}
$sfn = $info['fn'];
$sql = "INSERT INTO mutate (id,fn) VALUES ('{$sid}','{$sfn}')";
mysql_query($sql, $db) or die(mysql_error($db));
$sql = "DELETE FROM sorted where id='{$sid}' ";
mysql_query($sql, $db) or die(mysql_error($db));
$t++;
}
$sql = "SELECT * FROM mutate order by RAND() ";
$sql = mysql_query($sql, $db) or die(mysql_error($db));
$t = 0;
while ($info = mysql_fetch_array($sql)) {
$ms[$t] = $info['id'];
$t++;
}
mutate($ms[0], $ms[1]);
mutate($ms[2], $ms[3]);
$sql = "SELECT * FROM sorted order by RAND() ";
$sql = mysql_query($sql, $db) or die(mysql_error($db));
$t = 0;
while ($info = mysql_fetch_array($sql)) {
$cos[$t] = $info['id'];
$t++;
}
crossover($cos[0], $cos[1]);
crossover($cos[2], $cos[3]);
crossover($cos[4], $cos[5]);
crossover($cos[6], $cos[7]);
crossover($cos[8], $cos[9]);
crossover($cos[10], $cos[11]);
crossover($cos[12], $cos[13]);
crossover($cos[14], $cos[15]);
while ($cpop < $POP_SIZE) {
// we are going to create the new population by grabbing members of the old population
// two at a time via roulette wheel selection.
$offspring1 = roulette($totalfitness, $population, $fitness);
$offspring2 = roulette($totalfitness, $population, $fitness);
// and crossover dependent on the crossover rate
$crossresult = crossover($offspring1, $offspring2);
if (isset($crossresult[0])) {
$offspring1 = $crossresult[0];
}
if (isset($crossresult[1])) {
$offspring2 = $crossresult[1];
}
// now mutate dependen on the mutation rate
$offspring1 = mutate($offspring1);
$offspring2 = mutate($offspring2);
// add the offsprings in the population with fitness at 0
$temppop[$cpop++] = $offspring1;
$temppop[$cpop++] = $offspring2;
}
// Reset fitness
$fitness = array();
for ($i = 0; $i < $POP_SIZE; $i++) {
$fitness[$i] = 0;
}
// Copy temp population to population
$population = $temppop;
if (!$found) {
printPopulation($population);
}
$iterations++;
