clBLAS  2.11
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example_snrm2.c

Example of how to use the clblasSnrm2 function.

/* ************************************************************************
* Copyright 2013 Advanced Micro Devices, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ************************************************************************/
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
/* Include CLBLAS header. It automatically includes needed OpenCL header,
* so we can drop out explicit inclusion of cl.h header.
*/
#include <clBLAS.h>
/* This example uses predefined matrices and their characteristics for
* simplicity purpose.
*/
static const size_t N = 7;
static cl_float X[] = {
1,
2,
-11,
17,
5,
6,
81,
};
static const int incx = 1;
static cl_float NRM2;
int
main(void)
{
cl_int err;
cl_platform_id platform = 0;
cl_device_id device = 0;
cl_context_properties props[3] = { CL_CONTEXT_PLATFORM, 0, 0 };
cl_context ctx = 0;
cl_command_queue queue = 0;
cl_mem bufX, bufNRM2, scratchBuff;
cl_event event = NULL;
int ret = 0;
int lenX = 1 + (N-1)*abs(incx);
/* Setup OpenCL environment. */
err = clGetPlatformIDs(1, &platform, NULL);
if (err != CL_SUCCESS) {
printf( "clGetPlatformIDs() failed with %d\n", err );
return 1;
}
err = clGetDeviceIDs(platform, CL_DEVICE_TYPE_GPU, 1, &device, NULL);
if (err != CL_SUCCESS) {
printf( "clGetDeviceIDs() failed with %d\n", err );
return 1;
}
props[1] = (cl_context_properties)platform;
ctx = clCreateContext(props, 1, &device, NULL, NULL, &err);
if (err != CL_SUCCESS) {
printf( "clCreateContext() failed with %d\n", err );
return 1;
}
queue = clCreateCommandQueue(ctx, device, 0, &err);
if (err != CL_SUCCESS) {
printf( "clCreateCommandQueue() failed with %d\n", err );
clReleaseContext(ctx);
return 1;
}
/* Setup clblas. */
err = clblasSetup();
if (err != CL_SUCCESS) {
printf("clblasSetup() failed with %d\n", err);
clReleaseCommandQueue(queue);
clReleaseContext(ctx);
return 1;
}
/* Prepare OpenCL memory objects and place vectors inside them. */
bufX = clCreateBuffer(ctx, CL_MEM_READ_ONLY, (lenX*sizeof(cl_float)), NULL, &err);
// Allocate 1 element space for NRM2
bufNRM2 = clCreateBuffer(ctx, CL_MEM_WRITE_ONLY, (sizeof(cl_float)), NULL, &err);
// Allocate minimum of N elements
scratchBuff = clCreateBuffer(ctx, CL_MEM_READ_WRITE, (2*N*sizeof(cl_float)), NULL, &err);
err = clEnqueueWriteBuffer(queue, bufX, CL_TRUE, 0, (lenX*sizeof(cl_float)), X, 0, NULL, NULL);
/* Call clblas function. */
err = clblasSnrm2(N, bufNRM2, 0, bufX, 0, incx, scratchBuff,
1, &queue, 0, NULL, &event);
if (err != CL_SUCCESS) {
printf("clblasSnrm2() failed with %d\n", err);
ret = 1;
}
else {
/* Wait for calculations to be finished. */
err = clWaitForEvents(1, &event);
/* Fetch results of calculations from GPU memory. */
err = clEnqueueReadBuffer(queue, bufNRM2, CL_TRUE, 0, sizeof(cl_float),
&NRM2, 0, NULL, NULL);
printf("Result Euclidean Norm: %f\n", NRM2);
}
/* Release OpenCL events. */
clReleaseEvent(event);
/* Release OpenCL memory objects. */
clReleaseMemObject(bufX);
clReleaseMemObject(bufNRM2);
clReleaseMemObject(scratchBuff);
/* Finalize work with clblas. */
/* Release OpenCL working objects. */
clReleaseCommandQueue(queue);
clReleaseContext(ctx);
return ret;
}