Add CUDA by Example examples.

[parallel_computing.git] / src / cuda_by_example / reverseArray_singleblock.cu

diff --git a/src/cuda_by_example/reverseArray_singleblock.cu b/src/cuda_by_example/reverseArray_singleblock.cu
new file mode 100644 (file)
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+++ b/src/cuda_by_example/reverseArray_singleblock.cu
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+/*
+ * Copyright 1993-2008 NVIDIA Corporation.  All rights reserved.
+ *
+ * NOTICE TO USER:
+ *
+ * This source code is subject to NVIDIA ownership rights under U.S. and
+ * international Copyright laws.  Users and possessors of this source code
+ * are hereby granted a nonexclusive, royalty-free license to use this code
+ * in individual and commercial software.
+ *
+ * NVIDIA MAKES NO REPRESENTATION ABOUT THE SUITABILITY OF THIS SOURCE
+ * CODE FOR ANY PURPOSE.  IT IS PROVIDED "AS IS" WITHOUT EXPRESS OR
+ * IMPLIED WARRANTY OF ANY KIND.  NVIDIA DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOURCE CODE, INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE.
+ * IN NO EVENT SHALL NVIDIA BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL,
+ * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS,  WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION,  ARISING OUT OF OR IN CONNECTION WITH THE USE
+ * OR PERFORMANCE OF THIS SOURCE CODE.
+ *
+ * U.S. Government End Users.   This source code is a "commercial item" as
+ * that term is defined at  48 C.F.R. 2.101 (OCT 1995), consisting  of
+ * "commercial computer  software"  and "commercial computer software
+ * documentation" as such terms are  used in 48 C.F.R. 12.212 (SEPT 1995)
+ * and is provided to the U.S. Government only as a commercial end item.
+ * Consistent with 48 C.F.R.12.212 and 48 C.F.R. 227.7202-1 through
+ * 227.7202-4 (JUNE 1995), all U.S. Government End Users acquire the
+ * source code with only those rights set forth herein.
+ *
+ * Any use of this source code in individual and commercial software must
+ * include, in the user documentation and internal comments to the code,
+ * the above Disclaimer and U.S. Government End Users Notice.
+ */
+
+// includes, system
+#include <stdio.h>
+#include <assert.h>
+
+// Simple utility function to check for CUDA runtime errors
+void checkCUDAError(const char *msg);
+
+// Part 1 of 1: implement the kernel
+__global__ void reverseArrayBlock(int *d_out, int *d_in)
+{
+       int in = threadIdx.x;
+       int out = blockDim.x - 1 - threadIdx.x;
+       d_out[out] = d_in[in];
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Program main
+////////////////////////////////////////////////////////////////////////////////
+int main(int argc, char **argv)
+{
+
+       // pointer for host memory and size
+       int *h_a;
+       int dimA = 256;
+
+       // pointer for device memory
+       int *d_b, *d_a;
+
+       // define grid and block size
+       int numBlocks = 1;
+       int numThreadsPerBlock = dimA;
+
+       // allocate host and device memory
+       size_t memSize = numBlocks * numThreadsPerBlock * sizeof(int);
+       h_a = (int *)malloc(memSize);
+       cudaMalloc((void **)&d_a, memSize);
+       cudaMalloc((void **)&d_b, memSize);
+
+       // Initialize input array on host
+       for (int i = 0; i < dimA; ++i) {
+               h_a[i] = i;
+       }
+       // Copy host array to device array
+       cudaMemcpy(d_a, h_a, memSize, cudaMemcpyHostToDevice);
+
+       // launch kernel
+       dim3 dimGrid(numBlocks);
+       dim3 dimBlock(numThreadsPerBlock);
+       reverseArrayBlock <<< dimGrid, dimBlock >>> (d_b, d_a);
+
+       // block until the device has completed
+       cudaThreadSynchronize();
+
+       // check if kernel execution generated an error
+       // Check for any CUDA errors
+       checkCUDAError("kernel invocation");
+
+       // device to host copy
+       cudaMemcpy(h_a, d_b, memSize, cudaMemcpyDeviceToHost);
+
+       // Check for any CUDA errors
+       checkCUDAError("memcpy");
+
+       // verify the data returned to the host is correct
+       for (int i = 0; i < dimA; i++) {
+               assert(h_a[i] == dimA - 1 - i);
+       }
+       // free device memory
+       cudaFree(d_a);
+       cudaFree(d_b);
+
+       // free host memory
+       free(h_a);
+
+       // If the program makes it this far, then the results are correct and
+       // there are no run-time errors.  Good work!
+       printf("Correct!\n");
+       return 0;
+}
+
+void checkCUDAError(const char *msg)
+{
+       cudaError_t err = cudaGetLastError();
+       if (cudaSuccess != err) {
+               fprintf(stderr, "Cuda error: %s: %s.\n", msg,
+                       cudaGetErrorString(err));
+               exit(EXIT_FAILURE);
+       }
+}