When I use NPP signal statistical functions (such as nppMinMax_32f, nppSum_32f), the library runs the code without error, but the output values do not change. For example, in the following code, although the ‘pSrc’ memory is set to zero, the ‘Sum’ variable stays 1 after summing over ‘pSrc’.
I’m running this code in Visual C++ 2010 under Windows 7 x64 and NPP library version 5. Could you please tell me what is wrong?
int nLength = 100 ;
Npp32f * pSrc ;
NppStatus nError ;
// Get Memory
cudaMalloc( ( void ** ) & pSrc , nLength * sizeof( float ) ) ;
nError = nppsZero_32f( pSrc , nLength ) ;
// Compute the appropriate size of the scratch-memory buffer
Npp8u * pDeviceBuffer;
cudaMalloc((void **)& pDeviceBuffer, nBufferSize);
// Call the primitive with the scratch buffer
Npp32f Sum = 1.0f ;
nError = nppsSum_32f(pSrc, nLength, & Sum, pDeviceBuffer);
What happens if you add error checking to all CUDA API calls? I am not familiar with NPP. I note that the code passes a pointer to host memory to nppsSum_32f(). Is this as intended, or is NPP expecting a pointer to a device-side variable there?
I have tried your test case, the result is the same as yours. And I tried ippsSum_32f from IPP, it produces a sum 0. It seems a bug of NPP signal, could you please file a bug?
The input pointers are from device memory, but the output pointer must be to host memory. I added error checking to all commands but no error is returned.
It seems to be a bug related to all npps statistical functions. Could you tell me where can I file it?
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My mistake. The output pointers must be to device memory.
I have seen the bug you filed. Let us discuss it by mail.