Created
November 4, 2016 09:03
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#include <stdio.h> | |
#include <stdlib.h> | |
#include <time.h> | |
#include <cuda_runtime.h> | |
#include <math.h> | |
#define HILOS 45 | |
/** | |
* Sumatorio de los valores de un array mediante paralelismo en NVIDIA | |
*/ | |
__global__ void reduccionParalela(int array[]){ | |
int myID = threadIdx.x; | |
if(HILOS%2 != 0){ | |
if(myID == (HILOS-1)){ | |
array[0] += array[myID]; | |
} | |
} | |
int salto = HILOS/2; | |
__syncthreads(); | |
while(salto) | |
{ | |
// Solo trabajan la mitad de los hilos | |
if(myID < salto){ | |
array[myID] = array[myID] + array[myID+salto]; | |
} | |
__syncthreads(); | |
//Comprobamos que la mitad no sale impar y si es así se suma el valor perdido | |
if(salto % 2 != 0 && salto!=1){ | |
if(myID == salto-1){ | |
array[0] = array[0] + array[myID]; | |
} | |
} | |
__syncthreads(); | |
salto = salto/2; | |
} | |
//El valor ahora en array[0] es el doble exacto al que queremos, lo partimos y ya. //Solo funciona con enteros? | |
} | |
int main(int argc, char** argv){ | |
srand(time(NULL)); | |
int *hst_array = (int*) malloc(sizeof(int)*HILOS); | |
int *dev_array; | |
int total=0; | |
cudaMalloc((void**)&dev_array,sizeof(int)*HILOS); | |
for(int i = 0; i<HILOS;++i){ | |
hst_array[i]=i; | |
printf("%d ",hst_array[i]); | |
total += hst_array[i]; | |
} | |
cudaMemcpy(dev_array,hst_array,sizeof(int)*HILOS,cudaMemcpyHostToDevice); | |
reduccionParalela<<<1,HILOS>>> (dev_array); | |
cudaMemcpy(hst_array,dev_array,sizeof(int)*HILOS,cudaMemcpyDeviceToHost); | |
printf("\nReducción: %d - Bucle: %d\n",hst_array[0],total); | |
return 0; | |
} |
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