# Thursday, September 15, 2011
Word is starting to get out about C++ AMP, which appeared out of nowhere at a conference remarkably few Microsoft developers were paying attention to, because it was a hardware conference. There was information available in June, enough to get some of us excited:

I got into this right away and have been playing with code and doing a little writing. This is the kind of technology that changes things more than you might think. By leveraging the GPU, your code might run 10x faster, 50x faster, or even 100x faster. And for you to be able to do that from C++, using familiar C++ constructs, and a debugger and profiler in Visual Studio? That means everyone can do it.

Well, not quite everyone. You do have to learn how to parallelize your algorithms. The syntax of using the GPU (or some other heterogeneous computing resource) is not hard at all. The computer science of knowing your work is data parallel can be hard. But let me show you "not hard". Consider this code to add a pair of one-dimensional array:

void AddArrays(int n, int* pA, int* pB, int* pC)
{
    for (int i=0; i<n; i++) 
    {
            pC[i] = pA[i] + pB[i];
    }
}

Compare that to this:

#include <amp.h>
using namespace concurrency;
 
void AddArrays(int n, int * pA, int * pB, int * pC)
{
    array_view<int,1> a(n, pA);
    array_view<int,1> b(n, pB);
    array_view<int,1> c(n, pC);
 
    parallel_for_each(
        c.grid, 
        [=](index<1> idx) restrict(direct3d)
        {
            c[idx] = a[idx] + b[idx];
        }
     );
}

It's all C++ and it's all pretty readable. And this code runs on the GPU and can be WAY faster (and use less power, meaning your data centre is cheaper or your battery lasts longer) just like that.

Recently Daniel Moth has published ten blog posts drilling into some details. They will help if you've decided to start using AMP and want to know how. But before you do that, you might like to read a little background on why heterogeneous computing matters, what other options you might have for doing it, and why C++ AMP is what you want to use. I've done a small whitepaper on just that and would love you to read it and let me know what you think.

Kate



Thursday, September 15, 2011 9:15:16 AM (Eastern Daylight Time, UTC-04:00)  #    Comments [2]