Question

我正在尝试在C中编写一个MPI工作者，它将与用Python编写的MPI主机进行通信。主人将发送分散和收集，C工作人员应该通过收集接收这些并返回变量。问题是，我在编写工作文件时遇到了麻烦。

（工作者在C中的原因是因为这段代码是包含预先存在的python和C程序的骨架。）

这是我写的代码：

#include <stdio.h>
#include <mpi.h>

MPI_Comm comm;
MPI_Comm_get_parent(&comm);

int myid, world_size, size;
int root = 0;
int* endloop = malloc(sizeof(int));
int nelements1 = 1E3;
int nelements2 = 1E6;
float* input = malloc(sizeof(float) * nelements1);
float output[nelements2];

int randomarray(){
        float array[nelements2];
        srand(time(NULL));
        for( i = 0; i < nelements2; i++ ){
                array[i] = rand() % 0 + 1E6;
        }

        return array;

MPI_Comm_rank(MPI_COMM_WORLD, &myid);
MPI_Comm_size(MPI_COMM_WORLD, &world_size);
MPI_Comm_remote_size(comm, &size);

output = randomarray();

MPI_Scatter(endloop, 1, MPI_INT, root, comm);

while ( endloop[0] < 1) {
        MPI_Barrier(comm);
        MPI_Scatter(input, nelements1, MPI_FLOAT, root, comm);
        MPI_Barrier(comm);
        MPI_Gather(output, nelements2, MPI_FLOAT, root, comm);
        MPI_Scatter(endloop, 1, MPI_INT, root, comm);
}

MPI_Finalize();

我尝试编译时输出的错误是：

maddie@exo:~/code/bart_commloop$ mpicc worker.c -o worker
worker.c:5:21: error: expected declaration specifiers or ‘...’ before ‘&’ token
worker.c:9:16: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default]
worker.c:9:1: error: initializer element is not constant
worker.c:12:1: error: initializer element is not constant
worker.c:13:7: error: variably modified ‘output’ at file scope
worker.c: In function ‘randomarray’:
worker.c:18:7: error: ‘i’ undeclared (first use in this function)
worker.c:18:7: note: each undeclared identifier is reported only once for each function it appears in
worker.c:19:21: warning: division by zero [-Wdiv-by-zero]
worker.c:22:2: warning: return makes integer from pointer without a cast [enabled by default]
worker.c:22:2: warning: function returns address of local variable [enabled by default]
worker.c:28:8: error: incompatible types when assigning to type ‘float[1]’ from type ‘int’
worker.c:30:1: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:30:1: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:30:1: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:34:2: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:34:2: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:34:2: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:36:2: warning: passing argument 4 of ‘MPI_Gather’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1058:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:36:2: warning: passing argument 5 of ‘MPI_Gather’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1058:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:36:2: error: too few arguments to function ‘MPI_Gather’
/usr/lib/openmpi/include/mpi.h:1058:20: note: declared here
worker.c:37:2: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:37:2: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:37:2: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:40:1: error: expected declaration or statement at end of input

问题似乎是我的MPI调用的格式化，但我不确定在那里修复什么。

任何帮助都将非常赞赏。谢谢！

Python MPI master和C MPI worker之间的相互通信？

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