Source code that accompanies The CUDA Handbook.
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/*
*
* nbody_CPU_AOS.h
*
* Scalar CPU implementation of the O(N^2) N-body calculation.
*
* Copyright (c) 2011-2012, Archaea Software, LLC.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef NO_CUDA
#define NO_CUDA
#endif
#include <chCUDA.h>
#include <chTimer.h>
#include "bodybodyInteraction.cuh"
float
ComputeGravitation_AOS(
float *force,
float *posMass,
float softeningSquared,
size_t N
)
{
chTimerTimestamp start, end;
chTimerGetTime( &start );
for ( size_t i = 0; i < N; i++ )
{
float acc[3] = {0, 0, 0};
float myX = posMass[i*4+0];
float myY = posMass[i*4+1];
float myZ = posMass[i*4+2];
for ( size_t j = 0; j < N; j++ ) {
float fx, fy, fz;
float bodyX = posMass[j*4+0];
float bodyY = posMass[j*4+1];
float bodyZ = posMass[j*4+2];
float bodyMass = posMass[j*4+3];
bodyBodyInteraction<float>(
&fx, &fy, &fz,
myX, myY, myZ,
bodyX, bodyY, bodyZ, bodyMass,
softeningSquared );
acc[0] += fx;
acc[1] += fy;
acc[2] += fz;
}
force[3*i+0] = acc[0];
force[3*i+1] = acc[1];
force[3*i+2] = acc[2];
}
chTimerGetTime( &end );
return (float) chTimerElapsedTime( &start, &end ) * 1000.0f;
}