MPI代码不能与2个节点，但与1 [英] MPI code does not work with 2 nodes, but with 1

问题描述

超级编辑：

添加广播步骤将导致两个进程打印 ncols 由主节点（从中我可以检查输出）。但为什么？我的意思是，所有的广播变量已经有一个值在他们的声明！ （偏离主题图片）。

Adding the broadcast step, will result in ncols to get printed by the two processes by the master node (from which I can check the output). But why? I mean, all variables that are broadcast have already a value in the line of their declaration!!! (off-topic image).

我有一些代码基于这示例。

我检查了集群配置是否正常， a href =http://stackoverflow.com/questions/212528/get-the-ip-address-of-the-machine>打印将运行到其上的计算机的IP ：

I checked that cluster configuration is OK, with this simple program, which also printed the IP of the machine that it would run onto:

int main (int argc, char *argv[])
{
  int rank, size;

  MPI_Init (&argc, &argv);      /* starts MPI */
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);        /* get current process id */
  MPI_Comm_size (MPI_COMM_WORLD, &size);        /* get number of processes */
  printf( "Hello world from process %d of %d\n", rank, size );
  // removed code that printed IP address
  MPI_Finalize();
  return 0;
}

打印每台机器的IP两次。

which printed every machine's IP twice.

EDIT_2

如果我只打印网格，对于一台计算机：

If I print (only) the grid, like in the example, I am getting for one computer:

Processes grid pattern:
0 1
2 3

和两个：

Processes grid pattern:

推荐答案

两个节点中的可执行文件不一样！

Executables were not the same in both nodes!

有一个非常困难的时间，所以当我有一个安装问题，我只是跳过它。所以现在，更改只会出现在一个节点中。代码会奇怪，除非一些（或所有）代码是相同的。

When I configured the cluster, I had a very hard time, so when I had a problem with mounting, I just skipped it. So now, the changes would appear only in one node. The code would behave weirdly, unless some (or all) of the code was the same.

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