我正在尝试并行化我的代码,但出现错误。我需要计算柯西问题(它已经完成),但我需要使用 OpenMP 库对其进行并行化。
我尝试使用 OpenMP 编写一些代码,但不起作用。
我创建了一个结构来收集结果。
struct Dots {
double par;
double x;
double y;
};
这是我带参数的目标函数。
int ode_func (double x, const double y[], double f[], void *params)
{
double mu = *(int *)params;
f[0] = x + 2 * y[0] / (1 + mu * mu);
return GSL_SUCCESS;
}
这是主要功能。我目前没有找到如何创建结构体数组的方法,但这不是主要问题。
void calc_cauchy_problem(struct Dots ArrayOfDots[], double x_start, double x_end, double y_start,
int count) {
int dim = 1;
double x = x_start;
double y[1] = {y_start};
int mu = 5;
int param = 0;
gsl_odeiv2_system sys = {ode_func, NULL, dim, ¶m};
gsl_odeiv2_driver * d = gsl_odeiv2_driver_alloc_y_new (&sys,
gsl_odeiv2_step_rkf45, 1e-6, 1e-6, 0.0);
int status = 0;
#pragma omp parallel for shared(ArrayOfDots) private(sys, param, d, status)
for (int param = 1; param < mu; param++) {
gsl_odeiv2_system sys = {ode_func, NULL, dim, ¶m};
gsl_odeiv2_driver * d = gsl_odeiv2_driver_alloc_y_new (&sys,
gsl_odeiv2_step_rkf45, 1e-6, 1e-6, 0.0);
for (int i = 1; i <= count; i++)
{
double xi = x_start + i * (x_end - x_start) / count;
int status = gsl_odeiv2_driver_apply(d, &x, xi, y);
if (status != GSL_SUCCESS)
{
printf ("error, return value=%d\n", status);
break;
}
// ArrayOfDots[i].par = mu;
// ArrayOfDots[i].x = xi;
// ArrayOfDots[i].y = y[0];
}
gsl_odeiv2_driver_free (d);
}
}
主要内容
int main() {
double x_start = 0;
double x_end = 10;
double y_start = 0;
int count = 10;
struct Dots ArrayOfDots[count];
calc_cauchy_problem(ArrayOfDots, x_start, x_end, y_start, count);
return 0;
}
使用这个gcc main.c -o main -fopenmp -lgsl -std=gnu11
成功编译了它,但是当我启动它时出现错误
gsl: driver.c:354: ERROR: integration limits and/or step direction not consistent
Default GSL error handler invoked.
我认为这个 #pragma omp parallel for share(ArrayOfDots) private(sys, param, d, status) 的主要问题
但我不知道如何以其他方式重写它。
感谢您的回复。
更新:
有了 Kaveh Vahedipour 帮助我的代码部分开始工作。这意味着我的 for 循环的一半开始工作。
更新更新更新:
经过另一次调查后,我得到了以下代码:
它已编译并运行,但我的 Process finish with exit code 4
和 printf("Elapsed time = %f\n", omp_get_wtime() - start_time);
don'不打印任何内容。
struct Dots {
double par;
double x;
double y;
};
int ode_func (double x, const double y[], double f[], void *params)
{
double mu = *(int *)params;
f[0] = (x + 2 * y[0]) / (1 + mu * mu);
return GSL_SUCCESS;
}
void calc_cauchy_problem(double x_start, double x_end, double y_start,
int count, int param1, int param2) {
int dim = 1;
double x = x_start;
double y[1] = {y_start};
int param = param1;
int j = 0;
int status = 0;
char filename[10];
#pragma omp parallel for private(param, status, x, y)
for (param = param1; param <= param2; param++) {
struct Dots ArrayOfDots[count];
gsl_odeiv2_system sys = {ode_func, NULL, dim, ¶m};
gsl_odeiv2_driver * d =
gsl_odeiv2_driver_alloc_y_new (&sys, gsl_odeiv2_step_rkf45, 1e-6, 1e-6, 0.0);
for (int i = 1; i <= count; i++) {
double xi = x_start + i * (x_end - x_start) / count;
int status = gsl_odeiv2_driver_apply(d, &x, xi, y);
if (status != GSL_SUCCESS)
{
printf ("error, return value=%d\n", status);
break;
}
ArrayOfDots[i].par = param;
ArrayOfDots[i].x = xi;
ArrayOfDots[i].y = y[0];
}
gsl_odeiv2_driver_free (d);
}
}
int main() {
double start_time = omp_get_wtime();
double x_start = 0;
double x_end = 10;
double y_start = 0;
const int count = 500;
int param1 = 1;
int param2 = 10;
calc_cauchy_problem(x_start, x_end, y_start, count, param1, param2);
printf("Elapsed time = %f\n", omp_get_wtime() - start_time);
return 0;
}
最佳答案
将x
添加到私有(private)循环变量:private(sys, param, d, status, x)
。如果您仍然遇到问题,请回复我。
void calc_cauchy_problem(double x_start, double x_end, double y_start,
int count, int param1, int param2) {
int dim = 1;
double x = x_start;
double y[1] = {y_start};
int param = param1;
int j = 0;
int status = 0;
char filename[10];
#pragma omp parallel for private(param, status, x, y)
for (param = param1; param <= param2; param++) {
struct Dots ArrayOfDots[count];
gsl_odeiv2_system sys = {ode_func, NULL, dim, ¶m};
gsl_odeiv2_driver * d =
gsl_odeiv2_driver_alloc_y_new (&sys, gsl_odeiv2_step_rkf45, 1e-6, 1e-6, 0.0);
for (int i = 1; i <= count; i++) {
double xi = x_start + i * (x_end - x_start) / count;
int status = gsl_odeiv2_driver_apply(d, &x, xi, y);
if (status != GSL_SUCCESS)
{
printf ("error, return value=%d\n", status);
break;
}
ArrayOfDots[i].par = param;
ArrayOfDots[i].x = xi;
ArrayOfDots[i].y = y[0];
}
//write_data_to_file(param, count, ArrayOfDots);
for (int i = 0; i < count; ++i) {
printf ("%d: %f, %f, %f\n", omp_get_thread_num(),
ArrayOfDots[i].par, ArrayOfDots[i].x, ArrayOfDots[i].y);
}
gsl_odeiv2_driver_free (d);
}
}
关于c - OpenMP 并行 GSL 常微分方程计算,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56512937/