Martin Imre Martin Imre - 19 days ago 8
C++ Question

thrust copy_if: incomplete type is not allowed

I'm trying to use thrust::copy_if to compact an array with a predicate checking for positive numbers:

header file: file.h:

struct is_positive
{
__host__ __device__
bool operator()(const int x)
{
return (x >= 0);
}
};


and file.cu

#include "../headers/file.h"
#include <thrust/device_ptr.h>
#include <thrust/device_vector.h>
#include <thrust/copy.h>


void compact(int* d_inputArray, int* d_outputArray, const int size)
{
thrust::device_ptr<int> t_inputArray(d_inputArray);
thrust::device_ptr<int> t_outputArray(d_outputArray);
thrust::copy_if(t_inputArray, t_inputArray + size, d_outputArray, is_positive());
}


I'm getting error messages starting with:


/usr/local/cuda/include/thrust/system/detail/generic/memory.inl(40):
error: incomplete type is not allowed


full errormsg here

If I just use copy instead of copy_if, the code compiles fine, so I ruled everything except the predicate is_positive() out.

Thank you in advance for any help or general tips on how to debug such thrust errors.

e: I'm using Cuda 7.5

Answer

To me it looks like you just have a typo. This:

thrust::copy_if(t_inputArray, t_inputArray + size, d_outputArray, is_positive());
                                                   ^

should be this:

thrust::copy_if(t_inputArray, t_inputArray + size, t_outputArray, is_positive());

You've mixed a raw pointer with proper thrust device pointers, and this is causing trouble.

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