Starting from:

$25

GPGPU-Assignment_1 Solved

Assignment #1: The Big Dot 

The dot product of two vectors π‘Ž = (π‘Ž$,             π‘Žβ€™,                     …, π‘Ž()’ ) and 𝑏 = (𝑏$,               𝑏’,          β€¦, 𝑏()’ ), written π‘Ž βˆ™ 𝑏, is simply the sum of the component-by-component products:

             π‘Ž βˆ™ 𝑏 = βˆ‘(-/)$’ π‘Ž- Γ— 𝑏-

Dot products are used extensively in computing and have a wide range of applications. For instance, in 3D graphics (n = 3), we often make use of the fact that π‘Ž βˆ™ 𝑏 = |π‘Ž||𝑏|π‘π‘œπ‘ πœƒ, where | | denotes vector length and πœƒ is the angle between the two vectors.  In this assignment, you are expected to:

1.     Write CUDA code to compute in parallel the dot product of two (possibly large N = 100,000, or N = 1024*1024) random single precision floating point vectors;

2.     Write two functions to compute the results on the CPU and GPU, and compare the two results to check for correctness (1.0e-6);

β€’      float *CPU_big_dot(float *A, float *B, int N);

β€’      float *GPU_big_dot(float *A, float *B, int N);

3.     Print performance statistics with timer function;

β€’      CPU: Tcpu = Total computation time for CPU_big_dot();

β€’      GPU: Tgpu = Total computation time for GPU_big_dot();

β€’      Memory allocation and data transfer from CPU to GPU time

β€’      Kernel execution time

β€’      Data transfer from GPU to CPU time

β€’      Speedup = CPU/GPU

4.     Analyze the performance results in a few sentences.

β€’      Which one runs faster?

β€’      What’s the reason for that? Problem size, overhead, etc.  

 

Timer functions #include <sys/time.h> long long start_timer() { struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_sec * 1000000 + tv.tv_usec;  

}

 

long long stop_timer(long long start_time, char *name) { struct timeval tv; gettimeofday(&tv, NULL);

long long end_time = tv.tv_sec * 1000000 + tv.tv_usec;

Printf(β€œ%s: %.5f sec\n”, name, ((float) (end_time – start_time)) /

(1000 * 1000));  return end_time – start_time;

}  

 

More products