我有一个解决数独游戏的程序,我已经按顺序工作,但现在我尝试使用openMP并行化它。函数solvePuzzle()
包含算法,我想在其中并行化for循环,但是当我在for循环之前添加#pragma omp parallel for
语句时,我收到此错误:fatal error C1001: An internal error has occurred in the compiler.
该功能的代码是solvePuzzle()
:
bool sudoku::solvePuzzle(int grid[CELL][CELL]) {
int row, col;
if (!findEmptyCell(grid, row, col))
return true;
#pragma omp parallel for
for (int num = 1; num <= 9; num++) {
if (checkAccuracy(grid, row, col, num)) {
grid[row][col] = num;
if (solvePuzzle(grid))
return true;
grid[row][col] = EMPTY_CELL;
}
}
return false;
}
以下是带有main的驱动程序,如果它有帮助:
#include "SudokuGrid.h"
using namespace std;
int main() {
sudoku sudoku;
clock_t t1, t2;
t1 = clock();
if (sudoku.readPuzzle("1.txt")) {
sudoku.printGrid(sudoku.grid);
}
else {
cout << "Incorrect file" << endl;
}
cout << endl;
if (sudoku.solvePuzzle(sudoku.grid) == true)
sudoku.printGrid(sudoku.grid);
else
printf("No solution exists");
t2 = clock();
printf("Time to execute = %1d ms\n", (t2 - t1));
return 0;
}
构建时出现完整错误:
1>------ Build started: Project: Sudoku, Configuration: Debug Win32 ------
1>SudokuGrid.cpp
1>c:\users\john\source\repos\sudoku\sudoku\sudokugrid.cpp(8): fatal error
C1001: An internal error has occurred in the compiler.
1>(compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 258)
1> To work around this problem, try simplifying or changing the program near
the locations listed above.
1>Please choose the Technical Support command on the Visual C++
1> Help menu, or open the Technical Support help file for more information
1>
1>Done building project "Sudoku.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
答案 0 :(得分:4)
总而言之,问题是从并行化for
循环内部返回。
#pragma omp parallel for
for (int num = 1; num <= 9; num++) {
...
if (solvePuzzle(grid))
return true; // BAD
...
}
}
&#34; OpenMP要求循环结构处理每次迭代。不允许打破循环(使用return,goto,break,throw或其他方法)。&#34;
所以解决方案是让循环遍历所有迭代(参见Breaking Out of Loops)。
bool solvePuzzle(int grid[CELL][CELL]) {
bool solved = false;
int row, col;
if (!findEmptyCell(grid, row, col))
return true;
#pragma omp parallel for
for (int num = 1; num <= 9; num++) {
#pragma omp flush (solved)
if (!solved && checkAccuracy(grid, row, col, num)) {
grid[row][col] = num;
if (solvePuzzle(grid)) {
solved = true;
#pragma omp flush (solved)
} else {
grid[row][col] = EMPTY_CELL;
}
}
}
return solved;
}