在 Stackoverflow.com 上使用以前代码中的代码的问题 - C 中的 OpenMp 生命游戏

Question

我试图在我的 visual studio IDE 中复制此 post 中的代码，但我遇到了一些错误，即使我没有更改代码的任何部分。代码来自这个post - Game of Life with OpenMP

这是来自 post -

的代码

// Swapping the two grids   
 #define SWAP_BOARDS( b1, b2 )  do { \
 char* temp = b1; \
 b1 = b2; \
 b2 = temp; \
 } while(0)

// Simplifying access to grid elements
   #define BOARD( G, X, Y )  ((G)[NC*(X)+(Y)])

 char* sequential_game_of_life (char* outgrid, char* ingrid, 
       const int nrows, const int ncols, const int gens_max) {

  const int NC = ncols;
  int curgen, i, j;

 for (curgen = 0; curgen < gens_max; curgen++)
   {

  for (i = 0; i < nrows; i++)
{
  for (j = 0; j < ncols; j++)
    {
      const int inorth = mod (i-1, nrows);
      const int isouth = mod (i+1, nrows);
      const int jwest = mod (j-1, ncols);
      const int jeast = mod (j+1, ncols);

      const char neighbor_count = 
    BOARD (ingrid, inorth, jwest) + 
    BOARD (ingrid, inorth, j) + 
    BOARD (ingrid, inorth, jeast) + 
    BOARD (ingrid, i, jwest) +
    BOARD (ingrid, i, jeast) + 
    BOARD (ingrid, isouth, jwest) +
    BOARD (ingrid, isouth, j) + 
    BOARD (ingrid, isouth, jeast);

      BOARD(outgrid, i, j) = alivep (neighbor_count, BOARD (ingrid, i, j));
    }
}
  SWAP_BOARDS( outgrid, ingrid );
}
  return outgrid;
 }

我收到以下错误 -

Errors 
     char* temp = b1 `--> expression must have a constant value`
     b1 = b2;    --> `expression must have a constant value`
     b2 = temp;  --> `expression must have a constant value`

此外，代码的最后一行显示错误 “无法识别的令牌”：

SWAP_BOARDS( outgrid, ingrid ); --> `unrecognized token`

请问我该如何解决这些问题？感谢您的时间和帮助。

Answer 1

在这里，我在评论中回答你的问题。 Game of Life 的棋盘应该是一个无限的、二维的正交正方形网格。通过连接棋盘的边缘可以'approximated'无穷大。为此，mod 函数应定义为模函数。

int mod(int x, int y){return x%y;}

rules of game of life 是：

任何有两个或三个活邻居的活细胞都会存活下来。
任何有三个活邻居的死细胞都会成为活细胞。
所有其他活细胞在下一代死亡。同样，所有其他死亡细胞保持死亡状态。

函数alivep就是上述规则的定义。有 2 个输入参数：存活邻居的数量和细胞状态（存活或死亡）。 return值是cell在下一个周期的状态。假设 0 表示死了，1 表示活着，下面是一个如何实现它的例子：

char alivep(int neighbours, char alive){
    if (alive && (neighbours==2 || neighbours==3)) return 1; 
    else { 
        if (neighbours==3) return 1; else return 0;
    }
}

放在一起，定义main函数，添加一个print_board函数来显示棋盘，下面是一个例子：

#include <string.h>
#include <stdio.h>

int mod(int x, int y){return x%y;}

char alivep(int neighbours, char alive){
    if (alive && (neighbours==2 || neighbours==3)) return 1; 
    else { 
        if (neighbours==3) return 1; else return 0;
    }
}

// Swapping the two grids   
 #define SWAP_BOARDS( b1, b2 ) { \
 char* temp = b1; \
 b1 = b2; \
 b2 = temp; \
 }

// Simplifying access to grid elements
#define BOARD( G, X, Y )  ((G)[ncols*(X)+(Y)])

char* sequential_game_of_life (char* outgrid, char* ingrid, 
       const int nrows, const int ncols, const int gens_max) {

 for (int curgen = 0; curgen < gens_max; curgen++){
    for (int i = 0; i < nrows; i++){
        for (int j = 0; j < ncols; j++){
            const int inorth = mod (i-1, nrows);
            const int isouth = mod (i+1, nrows);
            const int jwest = mod (j-1, ncols);
            const int jeast = mod (j+1, ncols);

            const char neighbor_count = 
            BOARD (ingrid, inorth, jwest) + 
            BOARD (ingrid, inorth, j) + 
            BOARD (ingrid, inorth, jeast) + 
            BOARD (ingrid, i, jwest) +
            BOARD (ingrid, i, jeast) + 
            BOARD (ingrid, isouth, jwest) +
            BOARD (ingrid, isouth, j) + 
            BOARD (ingrid, isouth, jeast);

            BOARD(outgrid, i, j) = alivep (neighbor_count, BOARD (ingrid, i, j));
        }
    }
    SWAP_BOARDS( outgrid, ingrid );
 }
 return outgrid;
}

void print_board(char* ingrid, int nrows, int ncols)
{
    for(int i=0;i<nrows;++i)
    {
        for(int j=0;j<ncols;++j)
        {
            printf("%c", BOARD(ingrid,i,j)==0 ? '.' : '*');            
        }
        printf("\n");
    }
}


int main(){
    const int NR=15;
    const int NC=15;
    const int GENS_MAX=20;

    char ingrid[NR*NC];
    char outgrid[NR*NC];
    memset(ingrid,0,NR*NC*sizeof(ingrid[0]));
    
    //draw an example pattern
    ingrid[5*NC+5]=1;
    ingrid[5*NC+6]=1;
    ingrid[5*NC+7]=1;
    ingrid[5*NC+8]=1;
    ingrid[6*NC+5]=1;
    ingrid[7*NC+5]=1;
    ingrid[8*NC+5]=1;
    ingrid[9*NC+5]=1;

    printf("Initial board\n");
    print_board(ingrid, NR, NC);

    char* out=sequential_game_of_life (outgrid, ingrid, NR, NC, GENS_MAX);
    
    printf("Final board\n");
    print_board(out, NR, NC);
}

在 Stackoverflow.com 上使用以前代码中的代码的问题 - C 中的 OpenMp 生命游戏

Issues from using code from a previous code here on Stackoverflow.com - Game of life in C with OpenMp

c

openmp