我希望 Java 1.8 中的这段代码能够在更多处理器上并行运行:
// Make iterations
for(int i = 0; i < numberOfIterations; i++) {
for(int m = 0; m < gridsize; m++) {
for(int n = 0; n < gridsize; n++) {
one_cell_generation(grid, grid2, m, n);
}
int n = 0;
}
}
这是生命游戏实现的代码的一部分。我怎样才能使其并行,以便函数 one_cell_ Generation
将在更多处理器(也许是线程?)上运行多次。我是 Java 新手。谢谢。这是我的生命游戏实现的完整代码:
package gameoflife;
public class GameOfLife {
public static int gridsize = 5;
public static int numberOfIterations = 100;
public static String liveCell = "x";
public static String deadCell = "o";
public static void main(String[] args) {
// Probability that cell is live in random order
double p = 0.1;
Boolean[][] grid = new Boolean[gridsize][gridsize];
Boolean[][] grid2 = new Boolean[gridsize][gridsize];
// Set up grid
for(int m = 0; m < gridsize; m++) {
for(int n = 0; n < gridsize; n++) {
grid[m][n] = false;
if(Math.random() < p) {
grid[m][n] = true;
}
// Copy grid
grid2[m][n] = grid[m][n];
}
}
// Make iterations
for(int i = 0; i < numberOfIterations; i++) {
for(int m = 0; m < gridsize; m++) {
for(int n = 0; n < gridsize; n++) {
one_cell_generation(grid, grid2, m, n);
}
int n = 0;
}
}
print_grid(grid);
}
public static void print_grid(Boolean[][] grid) {
for(int m = 0; m < gridsize; m++) {
for(int n = 0; n < gridsize; n++) {
if(grid[m][n] == false) {
System.out.print(deadCell);
} else {
System.out.print(liveCell);
}
}
System.out.println();
}
}
public static void one_cell_generation(Boolean[][] oldGrid, Boolean[][] newGrid, int m, int n) {
// count live and dead neighbors
int liveNeighbours = 0;
// iterate over neighbors
// check borders
if(m > 0) {
if(oldGrid[m-1][n] == true) {
liveNeighbours += 1;
}
if (n > 0) {
if(oldGrid[m-1][n-1] == true) {
liveNeighbours += 1;
}
}
if(n < (gridsize - 1)) {
if (oldGrid[m-1][n+1] == true) {
liveNeighbours += 1;
}
}
}
if (m < (gridsize - 1)) {
if (oldGrid[m+1][n] == true) {
liveNeighbours += 1;
}
if(n > 0) {
if(oldGrid[m+1][n-1] == true) {
liveNeighbours += 1;
}
}
if(n < (gridsize - 1)) {
if(oldGrid[m+1][n+1] == true) {
liveNeighbours += 1;
}
}
}
if (n > 0) {
if (oldGrid[m][n-1] == true) {
liveNeighbours += 1;
}
}
if(n < (gridsize - 1)) {
if(oldGrid[m][n+1] == true) {
liveNeighbours += 1;
}
}
// conway's game of life rules
// apply rules to new grid
if(liveNeighbours < 2 || liveNeighbours > 3) {
newGrid[m][n] = false;
}
if(liveNeighbours == 3) {
newGrid[m][n] = true;
}
}
}
最佳答案
外层循环是在不同代之间循环的时间序列,因此不能并行化而不影响最终结果。
两个内循环根据上一代的状态计算当前一代的状态,并且可以轻松并行化。
这是一种使用 parallel 的方法IntStream
:
static int numberOfIterations = 100;
static int gridSize = 5;
public static void main(String[] args) {
Boolean[][] grid1 = new Boolean[gridSize][gridSize];
Boolean[][] grid2 = new Boolean[gridSize][gridSize];
// initialize grids here
for(int i = 0; i < numberOfIterations; i++) {
// parallel processing
IntStream.range(0, gridSize * gridSize).parallel().forEach(mn -> {
int m = mn / gridSize;
int n = mn % gridSize;
oneCellGeneration(grid1, grid2, m, n);
});
// copy new grid to old grid here
}
}
public static void oneCellGeneration(Boolean[][] grid1, Boolean[][] grid2,
int m, int n) {
// your cell generation logic here
}
<小时/>
注释 1:我重命名了一些方法和变量以符合 Java 命名约定。
注2:您忘记在原始代码中完成(或开始)生成后将新网格复制到旧网格。
关于带参数传递的 Java 并行 for 循环,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59476807/