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POCuda doesn't calculate what it is expected to, just silently ignores my code
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  1. POCuda doesn't calculate what it is expected to, just silently ignores my code
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    copied!<p>I'm encountering a very strange problem: Mu 9800GT doesnt seem to calculate at all. I've tried all hello-worlds i've found in the internet, here's one of them:</p> <p>this program creates 1..100 array on hosts, sends it to device, calculates a square of each value, returns it to host, prints the results.</p> <pre><code>#include "stdafx.h" #include &lt;stdio.h&gt; #include &lt;cuda.h&gt; __global__ void square_array(float *a, int N) { int idx = blockIdx.x * blockDim.x + threadIdx.x; if (idx&lt;N) a[idx] = a[idx] * a[idx]; } // main routine that executes on the host int main(void) { float *a_h, *a_d; // Pointer to host &amp; device arrays const int N = 100; // Number of elements in arrays size_t size = N * sizeof(float); a_h = (float *)malloc(size); // Allocate array on host cudaMalloc((void **) &amp;a_d, size); // Allocate array on device // Initialize host array and copy it to CUDA device for (int i=0; i&lt;N; i++) a_h[i] = (float)i; cudaMemcpy(a_d, a_h, size, cudaMemcpyHostToDevice); // Do calculation on device: int block_size = 4; int n_blocks = N/block_size + (N%block_size == 0 ? 0:1); square_array &lt;&lt;&lt; n_blocks, block_size &gt;&gt;&gt; (a_d, N); // Retrieve result from device and store it in host array cudaMemcpy(a_h, a_d, sizeof(float)*N, cudaMemcpyDeviceToHost); // Print results for (int i=0; i&lt;N; i++) printf("%d %f\n", i, a_h[i]); // Cleanup free(a_h); cudaFree(a_d); } </code></pre> <p>so the output is expected to be:</p> <blockquote> <p>1 1.000</p> <p>2 4.000</p> <p>3 9.000 </p> <p>4 16.000</p> </blockquote> <p>.. I swear back in 2009 it worked perfectly (vista 32, deviceemu)</p> <p>now i get output:</p> <blockquote> <p>1 1.000</p> <p>2 2.000</p> <p>3 3.000</p> <p>4 4.000</p> </blockquote> <p>so my card doesnt do anything. What can be the problem? Configuration is: win7x64 visual studio 2010 32bit cuda toolkit 3.2 64bit</p> <p>compilation settings: cuda 3.2 toolkit, 32-bit target platform, deviceemu or not - doesnt matter, the results are the same.</p> <p>i also tried it on my vmware xp(32bit) visual studio 2008. the result is the same.</p> <p>Please help me, i barely made the programe to compile, now i need it to work.</p> <p>You can also view my project with all it needs from <a href="http://forums.nvidia.com/index.php?act=attach&amp;type=post&amp;id=24060" rel="nofollow">my post at nvidia forums</a> ( 2.7 kb)</p> <p>Thanks, Ilya</p>
 

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