71 lines
2.1 KiB
Plaintext
71 lines
2.1 KiB
Plaintext
//******************************************************************************
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//
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// File: Powers.cu
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// Package: edu.rit.gpu.example
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// Unit: Powers kernel function
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//
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// This C/CUDA source file is copyright (C) 2014 by Alan Kaminsky. All rights
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// reserved. For further information, contact the author, Alan Kaminsky, at
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// ark@cs.rit.edu.
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//
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// This C/CUDA source file is part of the Parallel Java 2 Library ("PJ2"). PJ2
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// is free software; you can redistribute it and/or modify it under the terms of
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// the GNU General Public License as published by the Free Software Foundation;
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// either version 3 of the License, or (at your option) any later version.
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//
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// PJ2 is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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//
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// A copy of the GNU General Public License is provided in the file gpl.txt. You
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// may also obtain a copy of the GNU General Public License on the World Wide
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// Web at http://www.gnu.org/licenses/gpl.html.
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//
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//******************************************************************************
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// Struct containing results of one calculation.
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typedef struct
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{
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int x;
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double sqrt_x;
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double curt_x;
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double x_sq;
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double x_cu;
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}
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powers_t;
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/**
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* Device kernel to compute powers of x.
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* <P>
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* Called with a one-dimensional grid of one-dimensional blocks, NB blocks, NT
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* threads per block.
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*
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* @param powers Pointer to array of powers structs.
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* @param N Array length.
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*
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* @author Alan Kaminsky
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* @version 03-Jun-2014
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*/
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extern "C" __global__ void computePowers
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(powers_t *powers,
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int N)
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{
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int thr, size, rank, i;
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double log_x;
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// Determine number of threads and this thread's rank.
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thr = threadIdx.x;
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size = gridDim.x*blockDim.x;
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rank = blockIdx.x*blockDim.x + thr;
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// Compute powers.
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for (i = rank; i < N; i += size)
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{
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log_x = log((double)(powers[i].x));
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powers[i].sqrt_x = exp(log_x/2);
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powers[i].curt_x = exp(log_x/3);
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powers[i].x_sq = exp(log_x*2);
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powers[i].x_cu = exp(log_x*3);
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}
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}
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