Question

我上下搜索寻找这个问题的一些帮助，尝试了各种解决方案等，但似乎无法追踪问题。我尝试并行化包含对NLopt库中的优化例程的调用的do循环（对于NLOpt，请参阅：http://ab-initio.mit.edu/wiki/index.php/NLopt）。这是我尝试做的一个玩具示例（对于更新calfun中的参数的子程序的额外调用，真正的问题要复杂得多）：

program tester

implicit none

! Include optimization package
include 'nlopt.f'

integer :: i,t,obs,J,MAXI=1000
real(kind=8) :: TOL = 0.0000001

! Optimization variables
real(kind=8), allocatable :: lb(:), ub(:), args(:,:)
integer(kind=8), allocatable :: opt(:)
integer, allocatable :: ires(:),val(:)

print*, 'How many times would you like to evaluate the optimization problem?'
read*, obs
print*, 'What is the size of the input vector?'
read*, J

allocate(lb(J))
allocate(ub(J))
allocate(args(J,obs))
allocate(opt(obs))
allocate(ires(obs))
allocate(val(obs))

do i=1,J
    lb(i) = -5
    ub(i) = 5
end do

!$OMP PARALLEL DO SHARED(lb,ub,args,opt,ires,val) PRIVATE(t,i,J,TOL,MAXI) 

do t=1,obs

    ! Call optimization routine
    call nlo_create(opt(t),NLOPT_LN_BOBYQA,J)
    ! Set Bounds
    call nlo_set_lower_bounds(ires(t), opt(t), lb(1:J))
    call nlo_set_upper_bounds(ires(t), opt(t), ub(1:J))
    call nlo_set_max_objective(ires(t), opt(t), calfun, 0)
    ! Set initial values
    do i=1,J
        args(i,t) = 0
    end do
    ! Set tolerance and stopping criteria
    call nlo_set_xtol_abs1(ires(t), opt(t), TOL)
    call nlo_set_maxeval(ires(t), opt(t), MAXI)
    ! Call optimizer
    call nlo_optimize( ires(t), opt(t), args(1:J,t), val(t) )
    call nlo_destroy( opt(t) )
end do
!$OMP END PARALLEL DO

! Write argmax to working directory
open(unit=2, file="out.txt") 
write(2,*) args
close(2)

contains

! Function to be optimized
subroutine calfun(val, dims, args, grad, need_grad, f_data)

integer :: dims, need_grad
real(kind=8) :: val, args(dims), grad(dims)
real(kind=8) :: f_data
real(kind=8) :: sq_in =0
real(kind=8) :: lin_in = 1

! Example function has the form -2*(Sum(x(i)^2)) + Prod x(i)
if (need_grad == 0) then
    do i=1,dims
        sq_in = -2*args(i)**2 + sq_in
        lin_in = args(i)*lin_in
    end do
    val = sq_in + lin_in
end if

end subroutine calfun
end program tester

我已按照此文档进行故障排除：

https://software.intel.com/en-us/articles/determining-root-cause-of-sigsegv-or-sigbus-errors

我也尝试在这篇帖子后重置堆栈大小：

Why Segmentation fault is happening in this openmp code?

以上编译并使用gfortran正确运行，如下所示：

$ gfortran -I/usr/local/include/ tester.f90 /usr/local/lib/libnlopt.a 
$ ./a.out

当我添加OpenMP标志时，它也会编译：

$ gfortran -fopenmp -I/usr/local/include/ tester.f90 /usr/local/lib/libnlopt.a

但是，即使设置（在Mac OSX上运行）

，我也会收到分段错误

$ ulimit -s 65532

使用回溯进行编译只会显示NLOpt包中的选项卡错误和未使用的伪参数。我不知道如何继续并真正需要并行化此操作。我是否需要手动进入NLOpt例程并使用threadprivate设置内容？我似乎无法找到关于此的良好文档。欣赏任何见解...

（P.S。：这是我的第一篇Stackexchange帖子。多年来，我一直是个狂热的读者。对我这么简单！谢谢！）

使用OpenMP和外部库的Fortran90分段错误

0 个答案: