Create v1_2.cu

v1_2.cu

@@ -0,0 +1,168 @@
+%%cu
+
+/*
+ * CUDA version:1.2(multiple threads per block)
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+
+// ***Modulo for negative numbers*** (useful only for the device - GPU. It is used in Ising function)
+__device__ int mod(int a, int b){
+	int r = a % b;
+    return r < 0 ? r + b : r;
+}
+
+
+
+// the mathematical formula that will be run on the GPU
+__global__ void Ising(int* older, int* newer, int n){
+
+	//***inputs***
+	// 'older' is the 2D square lattice that contains the initial info for the dipoles' moments
+	// 'newer' is the 2D square lattice that will be used for the model's procedure(a simple exchange)
+	// 'n' is the dimension of the square lattices
+	//***output***
+	// 'none': There is no output. The function does some calculations only.
+
+	int j = blockIdx.x * blockDim.x + threadIdx.x;
+	int i = blockIdx.y * blockDim.y + threadIdx.y;
+	int sum;
+	// build the new phase of the material(or just create the formula that describes our model)
+	if ( i < n && j < n ){
+		sum = older[n * i + j] + older[n * i + mod(j - 1, n)] + older[n * i + (j + 1) % n] + older[mod(i - 1, n) * n + j] + older[((i + 1) % n) * n + j];
+		if(sum > 0){
+			newer[n * i + j] = 1;
+		} else {
+			newer[n * i + j] = -1;
+		}
+	}
+	__syncthreads();
+}
+
+
+
+// swap implementation
+void swap(int **x, int **y){
+	int *temp = *x;
+	*x = *y;
+	*y = temp;
+}
+
+
+
+int main(void){
+
+	printf("\n");
+	printf("Let's begin");
+	printf("\n");
+
+	//***___CPU variables___***
+	int k = 10; // k iterations of the formula
+	int n = 8; // the dimensions of the square 2D lattice
+	int *G1, *G2; // the 2D square lattices stored in a form of an array
+
+	// 1st 2D square lattice initialization
+	G1 = (int *)malloc(n * n * sizeof(int));
+	// filling the 2D square lattice(array) with -1 or 1
+	for(int i = 0; i < n * n; i++){
+			int random = (rand() % 2); // random numbers between 0 and 1
+			if(random == 1){ // if random is 1 the G(i,j) is 1
+				G1[i] = 1;
+			} else { // if random is 0 the G(i,j) is -1
+				G1[i] = -1;
+			}
+	}
+
+	// 2nd 2D square lattice initialization
+	G2 = (int *)malloc(n * n * sizeof(int));
+
+	//***___GPU variables___***
+	int *CUDAG1, *CUDAG2; // the 2D square lattices(arrays) that will exist in the GPU
+
+  cudaMalloc((void**)&CUDAG1, n * n * sizeof(int));
+
+  cudaMalloc((void**)&CUDAG2, n * n * sizeof(int));	
+
+
+
+
+	printf("\n");
+	printf("Let's start the procedure!!!");
+	printf("\n");
+
+	//***___CUDA parameters___***
+	int m = 4; // for gpu blocks -> m*m blocks
+	dim3 dimGrid(m, m); // grid size / number of blocks
+	printf("m = : %d block_dimension \n", m);
+	int t = 2; // t*tpb(t*t threads per block)
+ 	dim3 dimBlock(t, t); // Block size / number of threads
+ 	printf("t = : %d threads dimension\n", t);
+
+
+	// initial state
+	printf("The initial state of the ferromagnetic substance is: \n");
+	for(int i = 0; i < n; i++){
+		for(int j = 0; j < n; j++){
+			printf(" %d ",G1[i * n + j]);
+		}
+		printf("\n");
+	}
+
+	//***___start stopwatch___***
+	clock_t begin = clock();
+
+	//***___k iterations___***
+	for(int i = 0 ; i < k ; i++){
+		printf("*****____ %d iteration: ____***** \n", i);
+		cudaMemcpy(CUDAG1, G1, n*n*sizeof(int), cudaMemcpyHostToDevice);
+		cudaMemcpy(CUDAG2, G2, n*n*sizeof(int), cudaMemcpyHostToDevice);
+		Ising<<<dimGrid, dimBlock>>>(CUDAG1, CUDAG2, n);
+		cudaMemcpy(G1, CUDAG1, n*n*sizeof(int), cudaMemcpyDeviceToHost);
+		cudaMemcpy(G2, CUDAG2, n*n*sizeof(int), cudaMemcpyDeviceToHost);
+		swap(&G1, &G2);
+		for(int l = 0; l < n; l++){
+			for(int j = 0; j < n; j++){
+				printf(" %d ",G1[l * n + j]);
+			}
+			printf("\n");
+		}
+	}
+
+	// stop stopwatch and print time
+	clock_t end = clock();
+
+	// The execution time
+	double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+
+	printf("\n");
+	printf("End of the procedure!!!");
+	printf("\n");
+
+	// print the execution time
+	printf("The time spent for execution was: %f \n", time_spent);
+
+
+	// print the finished state of the moments(the G1 array, because it holds the results after the last swap)
+
+	/*
+	printf("The final state of the ferromagnetic substance is: \n");
+	for(int i = 0; i < n; i++){
+		for(int j = 0; j < n; j++){
+			printf(" %d ",G1[i * n + j]);
+		}
+		printf("\n");
+	}
+	*/
+
+	// free the memory, do not need it anymore
+	cudaFree(CUDAG1);
+	cudaFree(CUDAG2);
+	free(G1);
+	free(G2);
+
+	return 0;
+}