MPI_Gather 在最基本的代码中给出了段错误 [英] MPI_Gather gives seg fault in the most basic code
问题描述
我正在开发一个更大的程序,我在其中遇到了 MPI_Gather.
I am working on a much bigger program where I struggle with MPI_Gather.
我写了一个最小的示例代码,见下文.
I wrote a minimal example code, see below.
program test
use MPI
integer :: ierr, rank, size
double precision, allocatable, dimension(:) :: send, recv
call MPI_Init(ierr)
call MPI_Comm_size(MPI_COMM_WORLD, size, ierr)
if (ierr /= 0) print *, 'Error in MPI_Comm_size'
call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierr)
if (ierr /= 0) print *, 'Error in MPI_Comm_size'
allocate(send(1), recv(size))
send(1) = rank
call MPI_Gather(send, 1, MPI_DOUBLE_PRECISION, &
recv, 1, MPI_DOUBLE_PRECISION, 0, MPI_COMM_WORLD)
print *, recv
call MPI_Finalize(ierr)
end program test
当(有 2 个节点)我得到以下错误输出.
When (with 2 nodes) I get the following error output.
[jorvik:13887] *** Process received signal ***
[jorvik:13887] Signal: Segmentation fault (11)
[jorvik:13887] Signal code: Address not mapped (1)
[jorvik:13887] Failing at address: (nil)
[jorvik:13888] *** Process received signal ***
[jorvik:13888] Signal: Segmentation fault (11)
[jorvik:13888] Signal code: Address not mapped (1)
[jorvik:13888] Failing at address: (nil)
[jorvik:13887] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36150) [0x7f6ab77f8150]
[jorvik:13887] [ 1] /usr/lib/libmpi_f77.so.0(PMPI_GATHER+0x12d) [0x7f6ab7ebca9d]
[jorvik:13887] [ 2] ./test() [0x4011a3]
[jorvik:13887] [ 3] ./test(main+0x34) [0x401283]
[jorvik:13887] [ 4] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed) [0x7f6ab77e376d]
[jorvik:13887] [ 5] ./test() [0x400d59]
[jorvik:13887] *** End of error message ***
[jorvik:13888] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36150) [0x7f0ca067d150]
[jorvik:13888] [ 1] /usr/lib/libmpi_f77.so.0(PMPI_GATHER+0x12d) [0x7f0ca0d41a9d]
[jorvik:13888] [ 2] ./test() [0x4011a3]
[jorvik:13888] [ 3] ./test(main+0x34) [0x401283]
[jorvik:13888] [ 4] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed) [0x7f0ca066876d]
[jorvik:13888] [ 5] ./test() [0x400d59]
[jorvik:13888] *** End of error message ***
我做错了什么?MPI 肯定已在我使用的机器上安装并运行.
What am I doing wrong? MPI is definitely installed and running on the machine I am using.
推荐答案
最大的问题是您没有在对 MPI_Gather
的调用中包含最后一个 arg ierr.医生说
The big problem is that you did not include the last arg ierr in the call to MPI_Gather
. The doc said
Fortran 中的所有 MPI 例程(MPI_WTIME 和 MPI_WTICK 除外)在参数列表的末尾都有一个额外的参数 ierr.
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) have an additional argument ierr at the end of the argument list.
除此之外,我的建议是始终坚持良好的做法:不要为变量使用内部函数名称,例如 size
.
In addition to that, my advise is to always stick to good practice: Do not use intrinsic funtion names for your variable, example of size
.
program test
use MPI
integer :: ierr, rank, nProc
double precision, allocatable, dimension(:) :: send, recv
call MPI_Init(ierr)
if (ierr /= 0) print *, 'Error in MPI_Init'
call MPI_Comm_size(MPI_COMM_WORLD, nProc, ierr)
if (ierr /= 0) print *, 'Error in MPI_Comm_size'
call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierr)
if (ierr /= 0) print *, 'Error in MPI_Comm_size'
allocate(send(1), recv(nProc))
send(1) = rank
call MPI_Gather(send, 1, MPI_DOUBLE_PRECISION, &
recv, 1, MPI_DOUBLE_PRECISION, 0, MPI_COMM_WORLD, ierr)
if (ierr /= 0) print *, 'Error in MPI_Gather'
print *, recv
call MPI_Finalize(ierr)
end program test
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