On Tue, 29 May 2012 18:16:52 -0400, Thomas Wiecki <thomas_wie...@brown.edu>
wrote:
> Hi,
>
> I saw a couple of times the following idiom being used:
>
> const int tidx = blockIdx.x*blockDim.x + threadIdx.x;
> const int delta = blockDim.x*gridDim.x;
>
> curandState local_state = global_state[tidx];
>
> for (int idx = tidx; idx < n; idx += delta)
> {
> out[idx] = compute_sth(in[idx])
> }
>
> I'm not sure I 100% understand what's going on but it is looping over
> parts of the array spread dt apart. I think however in the case there
> are enough threads available (n < max_threads) only one thread would
> be doing all the work -- is that correct?
>
> Wouldn't a better idiom do sth along the lines of:
>
> for (int idx = tidx; idx < n; idx += max_threads)
>
> thus if n < max_threads it would loop only once per thread and scale
> up seamlessly. Am I missing something?These two look exactly the same to me, except you called "delta" "max_threads". I'm really squinting hard, I can't find a difference... Andreas
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