dpc＆＃x2b;＆＃x2B; ＆amp; MPI，缓冲区，共享内存，可变声明

发布于 2025-01-24 03:01:04 字数 1380 浏览 0 评论 0原文

我是DPC ++的新手，我尝试开发基于MPI的DPC ++泊松求解器。我读了这本书，对带有共享或主机备忘录的缓冲区和指针感到非常困惑。这两件事有什么区别，以及我在开发代码时应该使用什么。

现在，我使用由std ::阵列初始化的缓冲区，该缓冲区的串行代码大小为const大小，并且效果很好。但是，当我将DPC ++代码与MPI搭配时，我必须为每个设备声明一个本地长度，但是我没有这样做。在这里，我附加了我的代码

    define nx 359
    define ny 359
    constexpr int local_len[2];
    global_len[0] = nx + 1;
    global_len[1] = ny + 1;

    for (int i = 1; i < process; i++)
    {
        if (process % i == 0)
        {
            px = i;
            py = process / i;
            config_e = 1. / (2. * (global_len[1] * (px - 1) / py + global_len[0] * (py - 1) / px));
        }
        if (config_e >= cmax)
        {
            cmax = config_e;
            cart_num_proc[0] = px;
            cart_num_proc[1] = py;
        }
    }
    local_len[0] = global_len[0] / cart_num_proc[0];
    local_len[1] = global_len[1] / cart_num_proc[1];
    
    constexpr int lx = local_len[0];
    constexpr int ly = local_len[1];
    queue Q{};
    double *m_cellValue = malloc_shared<double>(size, Q);

，我收到的错误

error: default initialization of an object of const type 'const int[2]'
error: cannot assign to variable 'local_len' with const-qualified type 'const int[2]'
main.cpp:52:18: error: cannot assign to variable 'local_len' with const-qualified type 'const int[2]'

是否有任何方法可以定义一个可变大小数组以在DPC ++中进行并行操作？

原文

I am new to DPC++, and I try to develop a MPI based DPC++ Poisson solver. I read the book and am very confused about the buffer and the pointer with the shared or host memoery. What is the difference between those two things, and what should I use when I develop the code.

Now, I use the buffer initialized by an std::array with const size for serial code and it works well. However when I couple the DPC++ code with MPI, I have to declare a local length for each device, but I fail to do that. Here I attach my code

    define nx 359
    define ny 359
    constexpr int local_len[2];
    global_len[0] = nx + 1;
    global_len[1] = ny + 1;

    for (int i = 1; i < process; i++)
    {
        if (process % i == 0)
        {
            px = i;
            py = process / i;
            config_e = 1. / (2. * (global_len[1] * (px - 1) / py + global_len[0] * (py - 1) / px));
        }
        if (config_e >= cmax)
        {
            cmax = config_e;
            cart_num_proc[0] = px;
            cart_num_proc[1] = py;
        }
    }
    local_len[0] = global_len[0] / cart_num_proc[0];
    local_len[1] = global_len[1] / cart_num_proc[1];
    
    constexpr int lx = local_len[0];
    constexpr int ly = local_len[1];
    queue Q{};
    double *m_cellValue = malloc_shared<double>(size, Q);

I got the error

error: default initialization of an object of const type 'const int[2]'
error: cannot assign to variable 'local_len' with const-qualified type 'const int[2]'
main.cpp:52:18: error: cannot assign to variable 'local_len' with const-qualified type 'const int[2]'

Is there any way to just define a variable size array to do the parallel for in DPC++?

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