PGI User Forum

[SWL_EGGBABY]

I put the data into the GPU to run it, the result is wrong,why?

[mkcolg]

Hi SWL_EGGBABY,

There could be a number of possibilities. Can you please provide more details including sample code (if possible), compiler version, and OS? Also, please post your response to this topic. Posting new topics to each response makes it difficult for other users to follow the thread.

Thanks,
Mat

[SWL_EGGBABY]

Hi Mat,

The version is PGI Visual Fortran 2008 x64 10.2
The OS is windows xp 64-bit
The code is:

module mmul_mod
use cudafor
contains
attributes(global) subroutine mmul_kernel( A, B, C, N, M, L )
real :: A(N,M), B(M,L), C(N,L)
integer, value :: N, M, L
integer :: i, j, kb, k, tx, ty
real, shared :: Asub(16,16), Bsub(16,16)
real :: Cij
tx = threadidx%x
ty = threadidx%y
i = (blockidx%x-1) * 16 + tx
j = (blockidx%y-1) * 16 + ty
Cij = 0.0
do kb = 1, M, 16
Asub(tx,ty) = A(i,kb+ty-1)
Bsub(tx,ty) = B(kb+tx-1,j)
call syncthreads()
do k = 1,16
Cij = Cij + Asub(tx,k) * Bsub(k,ty)
enddo
call syncthreads()
enddo
C(i,j) = Cij
end subroutine mmul_kernel


subroutine mmul( A, B, C )
real, dimension(:,:) :: A, B, C
real, device, allocatable, dimension(:,:) :: Adev,Bdev,Cdev
type(dim3) :: dimGrid, dimBlock
N = size( A, 1 )
M = size( A, 2 )
L = size( B, 2 )
allocate( Adev(N,M), Bdev(M,L), Cdev(N,L) )
Adev = A(1:N,1:M)
Bdev(:,:) = B(1:M,1:L)
dimGrid = dim3( N/16, M/16, 1 )
dimBlock = dim3( 16, 16, 1 )
call mmul_kernel<<<dimGrid,dimBlock>>>( Adev, Bdev, Cdev, &
N, M, L )
C(1:N,1:L) = Cdev
deallocate( Adev, Bdev, Cdev )
end subroutine mmul
end module mmul_mod

program swl_eggbaby
use mmul_mod
implicit none
integer,parameter :: N=16,M=16,L=4
integer :: i
real :: A(N,M)=0
real :: B(M,L)=0
real :: C(N,L)
call mmul(A,B,C)
write(*,*) "计算结果:"
do i=1,N
write(*,*) C(N,:)
end do
end program

run it
计算结果:
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
-7.2750384E+34 NaN -4.8118824E-35 -1.7518910E-15
请按任意键继续. . .[/img]
thank you

[SWL_EGGBABY]

Device Number: 0
Device Name: Quadro FX 5800
Total Global Memory: 0.000 Gbytes
sharedMemPerBlock: 16384 bytes
regsPerBlock: 16384
warpSize: 32
maxThreadsPerBlock: 512
maxThreadsDim: 512 x 512 x 64
maxGridSize: 65535 x 65535 x 1
ClockRate: 1.296 GHz
Total Const Memory: 65536 bytes
Compute Capability Revision: 1.3
TextureAlignment: 256 bytes
deviceOverlap: T
multiProcessorCount: 30
integrated: T
canMapHostMemory: T
Device Number: 1
Device Name: Tesla C1060
Total Global Memory: 0.000 Gbytes
sharedMemPerBlock: 16384 bytes
regsPerBlock: 16384
warpSize: 32
maxThreadsPerBlock: 512
maxThreadsDim: 512 x 512 x 64
maxGridSize: 65535 x 65535 x 1
ClockRate: 1.296 GHz
Total Const Memory: 65536 bytes
Compute Capability Revision: 1.3
TextureAlignment: 256 bytes
deviceOverlap: T
multiProcessorCount: 30
integrated: T
canMapHostMemory: T

[mkcolg]

Hi SWL_EGGBABY,

Your code looks fine so I suspect that there is some issue with your cards. Try adding error checking to give us some ideas: