/*************************************************************************** copyright : (C) 2000 by Marko Grönroos email : magi@iki.fi *************************************************************************** * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later version. * * * *************************************************************************** * **/ #include #include #include #include "nbody.h" #include // sleep() ////////////////////////////////////////////////////////////////////////////// // ---- | // // | ) | // // |--- __ ---| \ | // // | ) / \ ( | \ | // // |___ \__/ ---| \_/ // // \_/ // ////////////////////////////////////////////////////////////////////////////// Coord Body::force (const Body& other, float& r) const return result { r = mPosition.dist (other.mPosition); result = (other.mPosition-mPosition)/(r*r*r) * other.mMass * mMass; } void Body::updateVelocity (const Coord& force) { mVelocity += force/mMass; } void Body::updatePosition (float h) { mPosition += mVelocity * h; } void Body::print (OStream& out) const { printf ("pos=(%f,%f), delta=(%f,%f), m=%f\n", mPosition.x, mPosition.y, mVelocity.x, mVelocity.y, mMass); } ////////////////////////////////////////////////////////////////////////////// // | | ---- | // // |\ | | ) | // // | \ | |--- __ ---| \ | // // | \| | ) / \ ( | \ | // // | | |___ \__/ ---| \_/ // // \_/ // ////////////////////////////////////////////////////////////////////////////// NBody::NBody (const StringMap& params, MPEWindow& mpe) : mrParams(params), mrMPE(mpe) { mBodies.make (int(params["NBody.n"])); mMinR = float(params["NBody.r"]); mViewCenter = Coord (float(params["viewCenter.x"]), float(params["viewCenter.y"])); mViewRadius = float(params["viewCenter.r"]); mUndraw = int(params["undraw"]); mDensity = int(params["NBody.density"]); } void NBody::init (const BodyIniter& initer) { for (int i=0; i plotCoords (mBodies.size); // Holds previous plot coordinates for (int i=0; i0) updatePositions (h, !(i%updateFreq), plotCoords); // Calculate forces (symmetrically) resetForces (); calculateForces (mBodies, mBodies, true); // Update velocity of the bodies updateVelocities (i? h : h/2); } } void NBody::resetForces () { for (int i=0; i& a, PackArray& b, bool diagonal) { float r; for (int i=0; imMinR) { a[i].addForce (force); b[j].addForce (-force); // Symmetric force } } } } void NBody::updateVelocities (float h) { for (int i=0; i& plotCoords) { for (int a=0; a plotCoords (mBodies.size); // Holds previous MPE plot coordinates sout.autoflush (true); // Create a double-buffered container for circulating bodies Array > circulatingBodies; circulatingBodies.add (new PackArray (mBodies.size)); // Create buffer #0 circulatingBodies.add (new PackArray (mBodies.size)); // Create buffer #1 int ringSize = mrMPI.world().size(); for (int iter=0; itergetType(), mNext); // Receive circulating bodies from previous node in the // ring. In the last step, we receive back the local // circulating bodies, which we sent out in the step=0. mrMPI.world().recv (circulatingBodies[(i+1)%2].data, 1, mpBodyVectorType->getType(), mPrev); } // Add the forces from the circulated local bodies to resident // bodies for (int i=0; i fields; body_s.split (fields, ','); body.setPosition (Coord (float(fields[0]), float(fields[1]))); body.setVelocity (Coord (float(fields[2]), float(fields[3]))); body.setMass (float(fields[4])); body.print (sout); } /////////////////////////////////////////////////////////////////////////////// // | | o // // |\ /| ___ _ // // | V | ___| | |/ \ // // | | | ( | | | | // // | | \__| | | | // /////////////////////////////////////////////////////////////////////////////// Main () { sout.printf ("sizeof(Body)=%d, sizeof(float)=%d\n", sizeof(Body), sizeof(float)); // Read application parameters from file readConfig ("/home/magi/c/opinnot/mpi/examples/nbody.cfg"); mParamMap.failByThrow (); MPIInstance mpi (mArgc, mArgv); MPEWindow mpe (mpi.world(), 0, 0, 400, 400, NULL); // Create the N-body system NBody* system; if (paramMap()["system"] == "NBody") system = new NBody (paramMap(), mpe); else if (paramMap()["system"] == "RingNBody") system = new RingNBody (paramMap(), mpe, mpi); else exit (1); // Initialize the system BodyIniter* initer; if (paramMap()["initer"] == "RandomIniter") initer = new RandomIniter (paramMap()); else if (paramMap()["initer"] == "PresetIniter") initer = new PresetIniter (paramMap()); else exit (1); system->init (*initer); // Run the system system->run (int(paramMap()["iters"]), float(paramMap()["h"]), int(paramMap()["update"])); printf ("Done.\n"); }