starpu-max/examples/spmv/spmv_opencl.cl

/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2010, 2012  Centre National de la Recherche Scientifique
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

__kernel void spmv(int nnz, int nrow,
                   __global float* nzval, __global unsigned* colind,
                   __global unsigned* rowptr, int firstentry,
                   __global float *vecin, int nx_in,
                   __global float *vecout, int nx_out)
{
	const int row = get_global_id(0);
	if (row < nrow)
	{
		float tmp = 0.0f;
		unsigned index;

		unsigned firstindex = rowptr[row] - firstentry;
		unsigned lastindex = rowptr[row+1] - firstentry;

		for (index = firstindex; index < lastindex; index++)
		{
			unsigned col;

			col = colind[index];
			tmp += nzval[index]*vecin[col];
		}

		vecout[row] = tmp;
	}
}