问题描述
/var/spool/torque/mom_priv/jobs/775.head.cluster.SC: line 22: 28084 Segmentation fault ./a.out
我是Fortran的新手，这是我第一次使用HPC和OpenMP.在我的代码中，我有一个应该并行的循环.我使用了一些动态变量，它们在并行循环中都是虚拟的.
I am new in Fortran and this is the first time I work with HPC and OpenMP.In my code, I have a loop that should be parallel. I use some dynamic variables that all of them are dummy in the parallel loop.
我在并行循环中分配动态变量
I allocate the dynamic variables in parallel loop
!$OMP PARALLEL DO
do 250 iconf = 1,config
allocate(randx(num),randy(num),randz(num),unit_cg(num), &
& x(nfftdim1),y(nfftdim2),z(nfftdim3),fr1(num), &
& fr2(num),fr3(num),theta1(order,num), &
& theta2(order,num),theta3(order,num), &
& Q(nfftdim1,nfftdim2,nfftdim3))
... call some subroutines and do calculations ...
deallocate(randx,randy,randz,unit_cg,fr1,fr2,fr3,theta1,theta2, &
& theta3,x,y,z,Q)
250 continue
!$OMP END PARALLEL DO
我省略了一些不相关的代码部分.执行程序时，会发生此错误:
I omited some irrelevant part of code. When the program is executed, this error occurs:
forrtl: severe (151): allocatable array is already allocated
我在并行区域之外分配了变量，它适用于较小的数据，但对于较大的数据，会发生此错误:
I allocated the variables outside the parallel region, it works for small data, but for large data this error occurs:
/var/spool/torque/mom_priv/jobs/775.head.cluster.SC: line 22: 28084 Segmentation fault ./a.out
我将PRIVATE子句用于动态变量(虚拟变量):
I used PRIVATE clause for dynamic variables (dummy variables):
!$OMP PARALLEL DO DEFAULT(SHARED) PRIVATE(randx,randy,randz, &
!$OMP& unit_cg,fr1,fr2,fr3,theta1,theta2,theta3,x,y,z,Q, &
!$OMP& dir_ene,rec_ene,corr_ene,energy_final,plproduct_avg, &
!$OMP& correlation_term)
并在并行循环内分配了变量，但存在相同的错误，最后，我将代码更改为:
and allocated variables inside parallel loop, but the same error,at last I changed the code to:
allocate(randx(num),randy(num),randz(num),unit_cg(num), &
& x(nfftdim1),y(nfftdim2),z(nfftdim3),fr1(num), &
& fr2(num),fr3(num),theta1(order,num), &
& theta2(order,num),theta3(order,num), &
& Q(nfftdim1,nfftdim2,nfftdim3))
!$OMP PARALLEL DO DEFAULT(SHARED) PRIVATE(randx,randy,randz, &
!$OMP& unit_cg,fr1,fr2,fr3,theta1,theta2,theta3,x,y,z,Q, &
!$OMP& dir_ene,rec_ene,corr_ene,energy_final,plproduct_avg, &
!$OMP& correlation_term)
do 250 iconf = 1,config
... call some subroutines and do calculations ...
250 continue
!$OMP END PARALLEL DO
deallocate(randx,randy,randz,unit_cg,fr1,fr2,fr3,theta1,theta2, &
& theta3,x,y,z,Q)
它在运行时失败.它启动了N个(线程数)循环，但无法完成循环，再次出现此错误:
it fails at run-time. it starts N (number of thread) loops, but can not complete them, and again this error:
/var/spool/torque/mom_priv/jobs/775.head.cluster.SC: line 22: 28084 Segmentation fault ./a.out
有什么主意吗?
推荐答案
我更改了代码，终于成功了！指令!$OMP PARALLEL DO是两个指令!$OMP PARALLEL和!$OMP DO的快捷方式.我使用了这两个指令(而不是!$OMP PARALLEL DO)并将分配放在并行区域内.我猜(但是我不确定)，现在编译器知道如何获取私有变量的内存，因为我在分配之前将private子句放在了前面，所以不会出现segmentation fault的情况.
I changed the code and finally it WORKS!The directive !$OMP PARALLEL DO is the shortcut of two directives !$OMP PARALLEL and !$OMP DO. I used these two directives (instead of !$OMP PARALLEL DO) and put allocation inside parallel region. I guess (but I'm not sure), now the compiler knows how to get memories for private variables, because I put private clause before allocation and so the segmentation fault dose not occur.
!$OMP PARALLEL DEFAULT(SHARED) PRIVATE(iconf,d,randx, &
!$OMP& randy,randz,unit_cg,theta1,theta2,theta3,fr1,fr2,fr3,Q, &
!$OMP& plproduct_avg)
allocate(randx(num),randy(num),randz(num),unit_cg(num), &
& fr1(num),fr2(num),fr3(num),theta1(order,num), &
& theta2(order,num),theta3(order,num), &
& Q(nfftdim1,nfftdim2,nfftdim3))
!$OMP DO
do 250 iconf = 1,config
... call some subroutines and do calculations ...
250 continue
!$OMP END DO
deallocate(randx,randy,randz,unit_cg,fr1,fr2,fr3,theta1,theta2, &
& theta3,Q)
!$OMP END PARALLEL
这篇关于forrtl:严重(151):可分配数组已分配-的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！