Hello,
I writing a Monte-Carlo random walk simulation, and if I do it with a large number of particles (300,000), I get a stack overflow error. I am confused as to what that error may signify.
Here are the gory details:
The error occurs in the routine execute_simulation (in red) in the following module (I include the module header). It occurs during the first loop of that routine. The routine execute_simulation is called from the main program.
module simulation_class
use misc_math_utilities
use particle_cloud_class
implicit none
type simulation
integer :: file_unit
REAL :: DT=1e-6
integer :: cMax_part=10,cMax_steps=10,iStep,seed_arr(2)=(/1,1/)
type (Particle_cloud) ::oParticle_cloud
real, dimension(3)::vRinit,vVinit
integer cPart
logical fPrint_av_KE
end type simulation
interface create_obj
module procedure create_simulation_obj
end interface
interface print_obj_def
module procedure print_simulation_obj_def
end interface
... other routines omitted ...
subroutine execute_simulation(self)
type (simulation) self
integer step
do step=1,self%cMax_steps
call take_step(self%oParticle_cloud)
call print_stats(self%oParticle_cloud,step)
end do
end subroutine execute_simulation
end module
The take_step routine is in the following module
MODULE particle_cloud_class
use misc_math_utilities
type particle_cloud
integer Count
real,allocatable::mStorage(:,:)
end type particle_cloud
integer iPart ! used for looping through particles
integer::viCoords(3)=(/1,2,3/),viVel(3)=(/4,5,6/)
interface create_obj
module procedure create_particle_cloud_obj
end interface
interface print_obj_def
module procedure print_particle_cloud_def
end interface
interface print_stats
module procedure print_R_stats
end interface
... stuff omitted
subroutine take_step(self)
type (particle_cloud)::self
real::temp(3)
self%mStorage(viCoords,:)=self%mStorage(viCoords,:)+self%mStorage(viVel,:)
do iPart=1,self%Count
temp=rn_point_on_sphere()
self%mStorage(viVel,iPart)=temp
end do
end subroutine t
ake_step
where rn_point_on_sphere() is a function that returns a 3-element vector of a random point on a sphere. I have tested that generator for up to 10^8 calls, and it seems to work ok.
I am not sure how to go and debug that error. Thanks for any pointers and suggestions.
Mirko
MADsblionel:
I mentioned earlier that the compiler would soon have an option to allocate temporaries on the heap. The good news is that it does, as of 9.1.029. The bad news is that support for the new switch, /heap-arrays as described in the release notes (which none of you read, apparently...), was inadvertently left out of the command driver in this release. It will get fixed for the next one. In the meantime, you can add this to the command line options:
