[英]Game of Life: Tried to increase computation efficiency with new algorithm, reduced in stead. Why?
我正在编写康威的生命游戏,并制作了一个工作顺畅的JS程序。 我在工作版本中做的是检查网格中每个坐标的每个相邻坐标,并根据其邻居数量杀死或生成它。 现在,我想通过跟踪哪些坐标是活着的,并且只处理那些和它们的邻居而不是整个网格来使算法更有效。 我做了这个替代计划:
var g = 0;
var cellMatrix = new Array();
var height = 68;
var width = 100;
var livingCellIndex = 0;
var livingCells = new Array();
writeBoard();
declareFirstGeneration();
live();
function live() {
processGeneration();
g++;
setTimeout(live, speed);
}
function declareNextGeneration() {
livingCells[g + 1] = new Array();
cellMatrix[g + 1] = new Array();
for (var x = 0; x < width; x++) {
cellMatrix[g + 1][x] = new Array();
for (var y = 0; y < height; y++) {
cellMatrix[g + 1][x][y] = false;
}
}
}
function declareFirstGeneration() {
livingCells[g] = new Array();
cellMatrix[g] = new Array();
for (var x = 0; x < width; x++) {
cellMatrix[g][x] = new Array();
for (var y = 0; y < height; y++) {
cellMatrix[g][x][y] = false;
}
}
}
function processGeneration() {
declareNextGeneration();
livingCellIndex = 0;
var x, y;
for (var i = 0; i < livingCells[g].length; i++) {
x = livingCells[g][i][0];
y = livingCells[g][i][1];
numberOfNeighbors = getLivingNeighbors(x, y);
//console.log("numberOfNeighbors", numberOfNeighbors);
if (numberOfNeighbors == 2 || numberOfNeighbors == 3) {
spawnCell(g + 1, x, y);
} else {
killCell(g + 1, x, y);
}
for (var neighborX = x - 1; neighborX <= x + 1; neighborX++) {
for (var neighborY = y - 1; neighborY <= y + 1; neighborY++) {
if (neighborX < width && neighborX >= 0 && neighborY < height && neighborY >= 0) {
numberOfNeighbors = getLivingNeighbors(neighborX, neighborY);
//console.log(g, neighborX, neighborY, "has ", numberOfNeighbors, " neighbors");
if (numberOfNeighbors == 3) {
spawnCell(g + 1, neighborX, neighborY);
}
}
}
}
}
refreshGenerationDisplay(x,y);
}
function spawnCell(g, x, y) {
cellMatrix[g][x][y] = true;
livingCells[g][livingCellIndex] = new Array(2);
livingCells[g][livingCellIndex][0] = x;
livingCells[g][livingCellIndex][2] = y;
document.getElementById(x + '-' + y).style.background = "green"; // visual grid
livingCellIndex++;
}
function killCell(g, x, y) {
cellMatrix[g][x][y] = false;
document.getElementById(x + '-' + y).style.background = "none"; // visual grid
}
但我发现它比我的第一个程序要慢得多。 似乎计算每一代的计算成本似乎随着每一代而增加。 这让我感到惊讶,因为我在这个替代算法中处理的数据较少。 我不确定它是否有意义,但这是第一个版本:
var g = 0;
var cellMatrix = new Array();
var height = 68;
var width = 100;
declareThisGeneration();
function live() {
g++;
processGeneration();
setTimeout(live, speed);
}
function processGeneration() {
if (oscillation) adjustGForOscillation();
if (g > 0) {
processNormalGeneration();
} else {
processFirstGeneration();
}
}
function processFirstGeneration() {
for (var x = 0; x < width; x++) {
for (var y = 0; y < height; y++) {
processFirstGenCell(g, x, y);
}
}
}
function processFirstGenCell(g, x, y) {
if (cellMatrix[g][x][y]) { //if alive
spawnCell(g, x, y);
} else { //if dead
killCell(g, x, y);
}
}
function processNormalGeneration() {
for (var x = 0; x < width; x++) {
for (var y = 0; y < height; y++) {
processCell(g, x, y);
}
}
}
function processCell(g, x, y) {
var livingNeighbors = getLivingNeighbors(g - 1, x, y);
if (cellMatrix[g - 1][x][y]) { //if alive
if (livingNeighbors != 2 && livingNeighbors != 3) {
killCell(g, x, y);
} else {
spawnCell(g, x, y);
}
} else { //if dead
if (livingNeighbors == 3) {
spawnCell(g, x, y);
} else {
killCell(g, x, y);
}
}
}
function spawnCell(g, x, y) {
cellMatrix[g][x][y] = true;
document.getElementById(x + '-' + y).className = 'alive';
}
function killCell(g, x, y) {
cellMatrix[g][x][y] = false;
document.getElementById(x + '-' + y).className = ''
}
我的问题是,是什么让“改进”的算法如此缓慢,我怎样才能降低成本呢?
版本1 //首先,最快
版本2 //新,慢
你不断在新版本中为每一代分配新的数组; 在旧版本中,您将继续重复使用相同的网格。 除了速度慢之外,如果不是因为速度慢,那么你的内存占用量会不断增长。
一种可能的解释是,如果你跟踪太多事情,计算机将需要分配更多的内存来存储它们,这需要时间。
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