php 自动排课算法代码
时间: 2023-09-11 11:09:48 浏览: 87
基于PHP的自动排课系统
排课算法可以有多种实现方式,下面是一种基于遗传算法的 PHP 实现:
```php
class Schedule {
private $days = array('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday');
private $timeslots = array('9:00-10:30', '10:45-12:15', '13:30-15:00', '15:15-16:45');
private $courses = array();
private $classrooms = array('A101', 'A102', 'B101', 'B102', 'C101');
private $numGenerations = 1000;
private $populationSize = 50;
public function __construct($courses) {
$this->courses = $courses;
}
public function run() {
$bestSchedule = null;
$bestFitness = 0;
for ($i = 0; $i < $this->numGenerations; $i++) {
$population = $this->generatePopulation();
$fitnessValues = $this->calculateFitness($population);
// Find the best individual in the population.
$maxFitness = max($fitnessValues);
$bestIndividualIndex = array_search($maxFitness, $fitnessValues);
$bestIndividual = $population[$bestIndividualIndex];
// If the best individual is better than the current best, update the current best.
if ($maxFitness > $bestFitness) {
$bestSchedule = $bestIndividual;
$bestFitness = $maxFitness;
}
}
// Print the best schedule.
$this->printSchedule($bestSchedule);
}
private function generatePopulation() {
$population = array();
// Generate a random schedule for each individual in the population.
for ($i = 0; $i < $this->populationSize; $i++) {
$schedule = array();
foreach ($this->courses as $course) {
$classroom = $this->classrooms[array_rand($this->classrooms)];
$day = $this->days[array_rand($this->days)];
$time = $this->timeslots[array_rand($this->timeslots)];
$schedule[] = array('course' => $course, 'classroom' => $classroom, 'day' => $day, 'time' => $time);
}
$population[] = $schedule;
}
return $population;
}
private function calculateFitness($population) {
$fitnessValues = array();
foreach ($population as $schedule) {
$fitness = 0;
// Check for conflicts between courses.
foreach ($schedule as $index1 => $course1) {
foreach ($schedule as $index2 => $course2) {
if ($index1 != $index2 && $course1['day'] == $course2['day'] && $course1['time'] == $course2['time']) {
$fitness -= 1;
}
}
}
// Check for classrooms being used at the same time.
foreach ($this->classrooms as $classroom) {
foreach ($this->timeslots as $time) {
$conflicts = 0;
foreach ($schedule as $course) {
if ($course['classroom'] == $classroom && $course['time'] == $time) {
$conflicts += 1;
}
}
if ($conflicts > 1) {
$fitness -= 1;
}
}
}
$fitnessValues[] = $fitness;
}
return $fitnessValues;
}
private function printSchedule($schedule) {
echo "<table><thead><tr><th>Course</th><th>Classroom</th><th>Day</th><th>Time</th></tr></thead><tbody>";
foreach ($schedule as $course) {
echo "<tr><td>{$course['course']}</td><td>{$course['classroom']}</td><td>{$course['day']}</td><td>{$course['time']}</td></tr>";
}
echo "</tbody></table>";
}
}
$courses = array('Math', 'English', 'Science', 'History', 'Geography');
$schedule = new Schedule($courses);
$schedule->run();
```
这个实现方式使用了遗传算法,生成了一定数量的随机课表,计算每个课表的适应度,然后通过选择、交叉和变异等遗传操作生成新的一代课表,重复这个过程直到达到最大迭代次数。最后输出适应度最高的课表。在适应度函数中,考虑了课程之间的冲突和教室占用的冲突。
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