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CentralDifference.cpp Go to the documentation of this file. /* ****************************************************************** ** ** OpenSees - Open System for Earthquake Engineering Simulation ** ** Pacific Earthquake Engineering Research Center ** ** ** ** ** ** (C) Copyright 1999, The Regents of the University of California ** ** All Rights Reserved. ** ** ** ** Commercial use of this program without express permission of the ** ** University of California, Berkeley, is strictly prohibited. See ** ** file 'COPYRIGHT' in main directory for information on usage and ** ** redistribution, and for a DISCLAIMER OF ALL WARRANTIES. ** ** ** ** Developed by: ** ** Frank McKenna (fmckenna@ce.berkeley.edu) ** ** Gregory L. Fenves (fenves@ce.berkeley.edu) ** ** Filip C. Filippou (filippou@ce.berkeley.edu) ** ** ** ** ****************************************************************** */ // $Revision: 1.5 $ // $Date: 2005/12/19 22:43:36 $ // $Source: /usr/local/cvs/OpenSees/SRC/analysis/integrator/CentralDifference.cpp,v $ // Written: Andreas Schellenberg (andreas.schellenberg@gmx.net) // Created: 02/05 // Revision: A // // Description: This file contains the implementation of the CentralDifference class. // // What: "@(#) CentralDifference.cpp, revA" #include <CentralDifference.h> #include <FE_Element.h> #include <LinearSOE.h> #include <AnalysisModel.h> #include <Vector.h> #include <DOF_Group.h> #include <DOF_GrpIter.h> #include <AnalysisModel.h> #include <Channel.h> #include <FEM_ObjectBroker.h> CentralDifference::CentralDifference() : TransientIntegrator(INTEGRATOR_TAGS_CentralDifference), alphaM(0.0), betaK(0.0), betaKi(0.0), betaKc(0.0), c2(0.0), c3(0.0), deltaT(0.0), Utm1(0), Ut(0), Utdot(0), Utdotdot(0), Udot(0), Udotdot(0) { } CentralDifference::CentralDifference( double _alphaM, double _betaK, double _betaKi , double _betaKc) : TransientIntegrator(INTEGRATOR_TAGS_CentralDifference), alphaM(_alphaM), betaK(_betaK), betaKi(_betaKi), betaKc(_betaKc), c2(0.0), c3(0.0), deltaT(0.0), Utm1(0), Ut(0), Utdot(0), Utdotdot(0), Udot(0), Udotdot(0) { } CentralDifference::~CentralDifference() { // clean up the memory created if (Utm1 != 0) delete Utm1; if (Ut != 0) delete Ut; if (Utdot != 0) delete Utdot; if (Utdotdot != 0) delete Utdotdot; if (Udot != 0) delete Udot; if (Udotdot != 0) delete Udotdot; } int CentralDifference::newStep(double _deltaT) { updateCount = 0; deltaT = _deltaT; if (deltaT <= 0.0) { opserr << "CentralDifference::newStep() - error in variable\n"; opserr << "dT = " << deltaT << endln; return -2; } // get a pointer to the AnalysisModel AnalysisModel *theModel = this->getAnalysisModelPtr(); // set the constants c2 = 0.5/deltaT; c3 = 1.0/(deltaT*deltaT); if (Ut == 0) { opserr << "CentralDifference::newStep() - domainChange() failed or hasn't been called\n"; return -3; } // increment the time and apply the load double time = theModel->getCurrentDomainTime(); theModel->applyLoadDomain(time); // determine the garbage velocities and accelerations at t Utdot->addVector(0.0, *Utm1, -c2); Utdotdot->addVector(0.0, *Ut, -2.0*c3); Utdotdot->addVector(1.0, *Utm1, c3); // set the garbage response quantities for the nodes theModel->setVel(*Utdot); theModel->setAccel(*Utdotdot); // set response at t to be that at t+deltaT of previous step (*Utdot) = *Udot; (*Utdotdot) = *Udotdot; return 0; } int CentralDifference::formEleTangent(FE_Element *theEle) { theEle->zeroTangent(); theEle->addCtoTang(c2); theEle->addMtoTang(c3); return 0; } int CentralDifference::formNodTangent(DOF_Group *theDof) { theDof->zeroTangent(); theDof->addCtoTang(c2); theDof->addMtoTang(c3); return(0); } int CentralDifference::domainChanged() { AnalysisModel *myModel = this->getAnalysisModelPtr(); LinearSOE *theLinSOE = this->getLinearSOEPtr(); const Vector &x = theLinSOE->getX(); int size = x.Size(); // if damping factors exist set them in the element & node of the domain if (alphaM != 0.0 || betaK != 0.0 || betaKi != 0.0 || betaKc != 0.0) myModel->setRayleighDampingFactors(alphaM, betaK, betaKi, betaKc); // create the new Vector objects if (Ut == 0 || Ut->Size() != size) { if (Utm1 != 0) delete Utm1; if (Ut != 0) delete Ut; if (Utdot != 0) delete Utdot; if (Utdotdot != 0) delete Utdotdot; if (Udot != 0) delete Udot; if (Udotdot != 0) delete Udotdot; // create the new Utm1 = new Vector(size); Ut = new Vector(size); Utdot = new Vector(size); Utdotdot = new Vector(size); Udot = new Vector(size); Udotdot = new Vector(size); // check we obtained the new if (Utm1 == 0 || Utm1->Size() != size || Ut == 0 || Ut->Size() != size || Utdot == 0 || Utdot->Size() != size || Utdotdot == 0 || Utdotdot->Size() != size || Udot == 0 || Udot->Size() != size || Udotdot == 0 || Udotdot->Size() != size) { opserr << "CentralDifference::domainChanged - ran out of memory\n"; // delete the old if (Utm1 != 0) delete Utm1; if (Ut != 0) delete Ut; if (Utdot != 0) delete Utdot; if (Utdotdot != 0) delete Utdotdot; if (Udot != 0) delete Udot; if (Udotdot != 0) delete Udotdot; Utm1 = 0; Ut = 0; Utdot = 0; Utdotdot = 0; Udot = 0; Udotdot = 0; return -1; } } // now go through and populate U, Udot and Udotdot by iterating through // the DOF_Groups and getting the last committed velocity and accel DOF_GrpIter &theDOFs = myModel->getDOFs(); DOF_Group *dofPtr; while ((dofPtr = theDOFs()) != 0) { const ID &id = dofPtr->getID(); int idSize = id.Size(); int i; const Vector &disp = dofPtr->getCommittedDisp(); for (i=0; i < idSize; i++) { int loc = id(i); if (loc >= 0) { (*Utm1)(loc) = disp(i); (*Ut)(loc) = disp(i); } } const Vector &vel = dofPtr->getCommittedVel(); for (i=0; i < idSize; i++) { int loc = id(i); if (loc >= 0) { (*Udot)(loc) = vel(i); } } const Vector &accel = dofPtr->getCommittedAccel(); for (i=0; i < idSize; i++) { int loc = id(i); if (loc >= 0) { (*Udotdot)(loc) = accel(i); } } } opserr << "WARNING: CentralDifference::domainChanged() - assuming Ut-1 = Ut\n"; return 0; } int CentralDifference::update(const Vector &U) { updateCount++; if (updateCount > 1) { opserr << "WARNING CentralDifference::update() - called more than once -"; opserr << " CentralDifference integration scheme requires a LINEAR solution algorithm\n"; return -1; } AnalysisModel *theModel = this->getAnalysisModelPtr(); if (theModel == 0) { opserr << "WARNING CentralDifference::update() - no AnalysisModel set\n"; return -1; } // check domainChanged() has been called, i.e. Ut will not be zero if (Ut == 0) { opserr << "WARNING CentralDifference::update() - domainChange() failed or not called\n"; return -2; } // check U is of correct size if (U.Size() != Ut->Size()) { opserr << "WARNING CentralDifference::update() - Vectors of incompatible size "; opserr << " expecting " << Ut->Size() << " obtained " << U.Size() << endln; return -3; } // determine the response at t+deltaT Udot->addVector(0.0, U, 3.0); Udot->addVector(1.0, *Ut, -4.0); Udot->addVector(1.0, *Utm1, 1.0); (*Udot) *= c2; Udotdot->addVector(0.0, *Udot, 1.0); Udotdot->addVector(1.0, *Utdot, -1.0); (*Udotdot) /= deltaT; // set response at t to be that at t+deltaT of previous step (*Utm1) = *Ut; (*Ut) = U; // update the response at the DOFs theModel->setResponse(U, *Udot, *Udotdot); if (theModel->updateDomain() < 0) { opserr << "CentralDifference::update() - failed to update the domain\n"; return -4; } return 0; } int CentralDifference::commit(void) { AnalysisModel *theModel = this->getAnalysisModelPtr(); if (theModel == 0) { opserr << "WARNING CentralDifference::commit() - no AnalysisModel set\n"; return -1; } // set the time to be t+deltaT double time = theModel->getCurrentDomainTime(); time += deltaT; theModel->setCurrentDomainTime(time); return theModel->commitDomain(); } int CentralDifference::sendSelf(int cTag, Channel &theChannel) { Vector data(4); data(0) = alphaM; data(1) = betaK; data(2) = betaKi; data(3) = betaKc; if (theChannel.sendVector(this->getDbTag(), cTag, data) < 0) { opserr << "WARNING CentralDifference::sendSelf() - could not send data\n"; return -1; } return 0; } int CentralDifference::recvSelf(int cTag, Channel &theChannel, FEM_ObjectBroker &theBroker) { Vector data(4); if (theChannel.recvVector(this->getDbTag(), cTag, data) < 0) { opserr << "WARNING CentralDifference::recvSelf() - could not receive data\n"; return -1; } alphaM = data(0); betaK = data(1); betaKi = data(2); betaKc = data(3); return 0; } void CentralDifference::Print(OPS_Stream &s, int flag) { AnalysisModel *theModel = this->getAnalysisModelPtr(); if (theModel != 0) { double currentTime = theModel->getCurrentDomainTime(); s << "\t CentralDifference - currentTime: " << currentTime << endln; s << " Rayleigh Damping - alphaM: " << alphaM; s << " betaK: " << betaK << " betaKi: " << betaKi << endln; } else s << "\t CentralDifference - no associated AnalysisModel\n"; } Generated on Mon Oct 23 15:04:58 2006 for OpenSees by  1.5.0

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