JS-错误:“无法读取未定义的属性”
问题描述:
我正在尝试使用P5.JS库在JavaScript中进行遗传算法模拟,但我遇到了一些问题。这是我到目前为止有:JS-错误:“无法读取未定义的属性”
//var popS = 2;
var popu;
//var balls = [];
var target;
function setup() {
createCanvas(800, 300);
popu = new Population();
target = createVector(width - 15, height/2);
}
function draw() {
background(50);
popu.run();
var ballsC = 0;
for (var a = 0; a < popu.balls.length; a++) {
if (popu.balls[a].done == true){
ballsC++;
}
}
if (ballsC >= popu.popS) {
//popu = new Population();
popu.evaluate();
//popu.selection();
}
fill(255, 0, 30);
noStroke();
ellipse(target.x, target.y, 20, 20);
}
function DNA() {
this.genes = [];
this.changes = 7;//random(2, 50);
for (var a = 0; a < this.changes; a++) {
this.genes[a] = random(0, 15);
}
this.crossover = function (pB) {
var newdna = new DNA();
var mid = floor(random(0, this.genes.length));
for (var a = 0; a < this.genes.length; a++) {
if (a < mid) {
newdna.genes[a] = this.genes[a];
}else {
newdna.genes[a] = pB.genes[a];
}
}
return newdna;
}
}
function Population() {
this.balls = [];
this.popS = 50;
this.maxfit = 0;
this.matingpool = [];
for (var a = 0; a < this.popS; a++) {
this.balls[a] = new Ball();
}
this.evaluate = function() {
for (var a = 0; a < this.balls.length; a++) {
this.balls[a].calcF();
if (this.balls[a].fitness > this.maxfit) {
this.maxfit = this.balls[a].fitness;
}
}
this.matingpool = [];
for (var b = 0; b < this.balls.length; b++) {
var n = this.balls[b].fitness * 100;
for (var c = 0; c < n; c++) {
this.matingpool.push(this.balls[c]);
}
}
this.selection();
}
this.selection = function() {
var newBalls = [];
for (var a = 0; a < this.balls.length; a++) {
var parentA = this.matingpool[floor(random(0, this.matingpool.length))];
var parentB = this.matingpool[floor(random(0, this.matingpool.length))];
var child = parentA.dna.crossover(parentB.dna);
newBalls[a] = new Ball(child);
}
this.balls = newBalls;
}
this.run = function() {
for (var a = 0; a < this.balls.length; a++) {
this.balls[a].update();
this.balls[a].checkCol();
this.balls[a].show();
}
}
}
function Ball(dna) {
this.pos = createVector(10, height/2);
this.speed = createVector(2, 2.5);
this.mul = -1;
this.time = 0;
this.a = 0;
if (dna) {
this.dna = dna;
} else {
this.dna = new DNA();
}
this.done = false;
this.fitness = 0;
this.reached;
this.update = function() {
if (this.done == false) {
if (this.time >= this.dna.genes[this.a]) {
this.a++;
this.time = 0;
this.mul *= -1;
}
this.speed.set(2, 2.5 * this.mul);
this.pos.add(this.speed);
}
}
this.show = function() {
this.time += 0.1;
fill(255, 70);
noStroke();
ellipse(this.pos.x, this.pos.y, 10, 10);
}
this.checkCol = function() {
if (this.pos.y > height || this.pos.y < 0 || this.pos.x > width) {
//print("col");
this.done = true;
}
if (dist(this.pos.x, this.pos.y, target.x, target.y) <= (10/2) + (20/2)) {
//print("done!");
this.done = true;
this.reached = true;
}
}
this.calcF = function() {
var a = dist(this.pos.x, this.pos.y, target.x, target.y);
var b = this.dna.genes.length;
var c = 0;
if (this.reached){
c = 1;
}
this.fitness = map(map(a, 0, width, 1, 0) + map(b, 2, 50, 1, 0) + c, 0, 3, 0, 1);
}
}
这是代码的最重要的部分:
var popu;
function setup() {
createCanvas(800, 300);
popu = new Population();
}
function draw() {
background(50);
//popu = new Population();
popu.evaluate();
//popu.selection();
}
function DNA() {
this.genes = [];
this.changes = 7; //random(2, 50);
for (var a = 0; a < this.changes; a++) {
this.genes[a] = random(0, 15);
}
this.crossover = function(pB) {
var newdna = new DNA();
var mid = floor(random(0, this.genes.length));
for (var a = 0; a < this.genes.length; a++) {
if (a < mid) {
newdna.genes[a] = this.genes[a];
} else {
newdna.genes[a] = pB.genes[a];
}
}
return newdna;
}
}
function Population() {
this.balls = [];
this.popS = 50;
this.maxfit = 0;
this.matingpool = [];
for (var a = 0; a < this.popS; a++) {
this.balls[a] = new Ball();
}
this.evaluate = function() {
this.matingpool = [];
for (var b = 0; b < this.balls.length; b++) {
var n = this.balls[b].fitness * 100;
for (var c = 0; c < n; c++) {
this.matingpool.push(this.balls[c]);
}
}
this.selection();
}
this.selection = function() {
var newBalls = [];
for (var a = 0; a < this.balls.length; a++) {
var parentA = this.matingpool[floor(random(0, this.matingpool.length))];
var parentB = this.matingpool[floor(random(0, this.matingpool.length))];
var child = parentA.dna.crossover(parentB.dna);
newBalls[a] = new Ball(child);
}
this.balls = newBalls;
}
}
function Ball(dna) {
this.pos = createVector(10, height/2);
this.speed = createVector(2, 2.5);
this.mul = -1;
this.time = 0;
this.a = 0;
if (dna) {
this.dna = dna;
} else {
this.dna = new DNA();
}
this.done = false;
this.fitness = 0;
this.reached;
}
所以一旦进入到这里:
this.selection = function() {
var newBalls = [];
for (var a = 0; a < this.balls.length; a++) {
var parentA = random(this.matingpool);
var parentB = random(this.matingpool);
var child = parentA.dna.crossover(parentB.dna);
newBalls[a] = new Ball(child);
}
this.balls = newBalls;
}
我得到的错误:“无法读取未定义的属性”dna“,为什么地球上会发生这种情况?当我在chrome中使用调试器时,我可以清楚地看到,配合池有2000个元素,但是当我尝试获取随机的元素时,它返回“undefined”。
var parentA = random(this.matingpool);
var parentB = random(this.matingpool);
奇怪的是,parentB工作,但parentA dosn't。
任何帮助深表感谢。整个代码运行在这里:http://codepen.io/felipe_mare/pen/bgOYMN
如果有帮助,我有时会得到错误:“不能读取属性‘0’的未定义”来代替,在管线138
this.update = function() {
if (this.done == false) {
//line 138
if (this.time >= this.dna.genes[this.a]) {
//line 138
this.a++;
this.time = 0;
this.mul *= -1;
}
this.speed.set(2, 2.5 * this.mul);
this.pos.add(this.speed);
}
}
答
在未来,请请请尝试把你的问题缩小到MCVE。我明白这是一个复杂的调试问题,但如果您尝试将问题缩小至最低最小(20行以下),则运气会好得多。大多数情况下,你最终会在创建MCVE的过程中发现你的错误。
但你的问题实际上是在创建matingpool
阵列,在这里:
this.matingpool = [];
for (var b = 0; b < this.balls.length; b++) {
var n = this.balls[b].fitness * 100;
for (var c = 0; c < n; c++) {
this.matingpool.push(this.balls[c]);
}
}
如果我添加打印语句内for
循环里面,像这样:
this.matingpool = [];
for (var b = 0; b < this.balls.length; b++) {
var n = this.balls[b].fitness * 100;
for (var c = 0; c < n; c++) {
console.log("pushing: " + this.balls[c]);
this.matingpool.push(this.balls[c]);
}
}
然后我看到你需要将undefined
排入阵列:
(1178) pushing: [object Object]
(3) pushing: undefined
(482) pushing: [object Object]
(3) pushing: undefined
(216) pushing: [object Object]
然后你从这个数组中随机选择,这就是为什么你的错误出现在你的代码中的随机地方。
你将不得不进一步调试以弄清楚为什么会发生这种情况 - 你基于适应性而不是数组长度循环似乎很奇怪,但我并不能很好地理解代码为了确定。无论如何,希望这能让你走上正确的道路。
你的'random()'看起来如何? – JohanP
@JohanP请注意[tag:p5.js]标签。 P5.js库提供'random()'函数。 –
哪一行是“138行”? – Li357