CUDA double/float woes CUDA not denoting double prec types?

Accelerated Computing CUDA CUDA Programming and Performance
1

I am having a strange problem with CUDA. Anytime I use a double type in my kernel function(s) things go very very wrong…

If I change ‘VARTYPE’ to float everything works.

I am using a 8600GT card which only has compute compatibility of 1.1. Both in this http://forums.nvidia.com/index.php?showtopic=33079 thread and the CUDA programming guide…

there is talk about a conversion for my device. I was under the impression that this was done automatically and did not have to worry about this. Now it seems I do. But no matter what kind of converts I try to do for the sample code below I do not get a sensible answer? What can I do except for converting everything in my application to floats?

See the sample code below:

#include <stdio.h>

#include <cutil.h>

#define VARTYPE double

//#define VARTYPE float

__global__ void test(VARTYPE *data) {

	int id  = threadIdx.x + threadIdx.y * gridDim.x;

	data[id] = id;

}

#define NB 512

int main() {

	dim3 blockSize(NB, 1);

	

	VARTYPE *dbg;

	VARTYPE res[NB];

	CUDA_SAFE_CALL(cudaMalloc((void**)&dbg, sizeof(*dbg) * NB));

	test<<<1, blockSize>>>(dbg);

	CUDA_SAFE_CALL(cudaMemcpy(res, dbg, sizeof(*res) * NB, cudaMemcpyDeviceToHost));

	CUT_CHECK_ERROR("1. kernel");

	CUDA_SAFE_CALL(cudaThreadSynchronize());

	for (int i = 0; i != NB; i++) printf("%3d %f\n", i + 1, res[i]);

	

	CUDA_SAFE_CALL(cudaFree(dbg));

}