Method update

SRC/analysis/integrator/CentralDifferenceAlternative.cpp:191–238

int
CentralDifferenceAlternative::update(const Vector &X)
{
  updateCount++;
  if (updateCount > 1) {
    opserr << "ERROR CentralDifferenceAlternative::update() - called more than once -";
    opserr << " Central Difference integraion schemes require a LINEAR solution algorithm\n";
    return -1;
  }
  
  AnalysisModel *theModel = this->getAnalysisModel();

  if (theModel == 0) {
    opserr << "ERROR CentralDifferenceAlternative::update() - no AnalysisModel set\n";
    return -2;
  }	
  
  // check domainChanged() has been called, i.e. Ut will not be zero
  if (Ut == 0) {
    opserr << "WARNING CentralDifferenceAlternative::update() - domainChange() failed or not called\n";
    return -2;
  }	

  // check deltaU is of correct size
  if (X.Size() != Ut->Size()) {
    opserr << "WARNING CentralDifferenceAlternative::update() - Vectors of incompatible size ";
    opserr << " expecting " << Ut->Size() << " obtained " << X.Size() << endln;
    return -3;
  }


  //  determine the displacement at t+delta t 
  Utp1->addVector(0.0, X, deltaT * deltaT);
  (*Utp1) += *Ut;
  Utp1->addVector(1.0, *Udot, deltaT);

  //  determine the vel at t+ 0.5 * delta t 
  (*Udot) =  *Utp1;
  (*Udot) -= *Ut;
  (*Udot) *= (1.0/deltaT);

  // update the disp & responses at the DOFs
  theModel->setDisp(*Utp1);
  theModel->setVel(*Udot);
  theModel->updateDomain();

  return 0;
  }    

int
CentralDifferenceAlternative::commit(void)