increment array test

1 files changed, 69 insertions, 0 deletions

diff --git a/incrementArrays.cu b/incrementArrays.cu
new file mode 100644
index 0000000..3f727b6
--- /dev/null
+++ b/incrementArrays.cu
@@ -0,0 +1,69 @@
+// incrementArrays.cu
+#include <stdio.h>
+#include <assert.h>
+#include <cuda.h>
+
+void incrementArrayOnHost(float *a, int N)
+{
+    int i;
+    for (i=0; i<N; i++) {
+        a[i] = a[i] + 1.f;
+    }
+}
+
+__global__ void incrementArrayOnDevice(float *a, int N)
+{
+    int idx = blockIdx.x * blockDim.x + threadIdx.x;
+    if (idx<N) {
+        a[idx] = a[idx] + 1.f;
+    }
+}
+
+int main(void)
+{
+    float *a_h, *b_h;       // pointers to host memory
+    float *a_d;             // pointer to device memory
+    int i, N = 10;
+    size_t size = N*sizeof(float);
+
+    // allocate arrays on host
+    a_h = (float *)malloc(size);
+    b_h = (float *)malloc(size);
+
+    // allocate array on device
+    cudaMalloc((void **) &a_d, size);
+
+    // initialization of host data
+    for (i=0; i<N; i++) {
+        printf("%.2f\n", i);
+        a_h[i] = (float) i;
+    }
+    printf("\n");
+
+    // copy data from host to device
+    cudaMemcpy(a_d, a_h, sizeof(float)*N, cudaMemcpyHostToDevice);
+
+    // do calculation on host
+    incrementArrayOnHost(a_h, N);
+
+    // do calculation on device
+    // 01 - compute execution configuration
+    int blockSize = 4;
+    int nBlocks = N/blockSize + (N%blockSize == 0?0:1);
+    // 02 - call incrementArrayOnDevice kernel
+    incrementArrayOnDevice <<< nBlocks, blockSize >>> (a_d, N);
+    
+    // Retrieve result from device and store in b_h
+    // (dst, src, count, kind)
+    cudaMemcpy(b_h, a_d, sizeof(float)*N, cudaMemcpyDeviceToHost);
+
+    // check result
+    for (i=0; i<N; i++) {
+        printf("%.2f\n", b_h[i]);
+        assert(a_h[i] == b_h[i]);
+    }
+
+    // cleanup
+    free(a_h); free(b_h); cudaFree(a_d);
+}
+