Method newStep

SRC/analysis/integrator/HHTGeneralized_TP.cpp:135–195

int HHTGeneralized_TP::newStep(double _deltaT)
{
    if (beta == 0 || gamma == 0 )  {
        opserr << "HHTGeneralized_TP::newStep() - error in variable\n";
        opserr << "gamma = " << gamma << " beta = " << beta << endln;
        return -1;
    }
    
    deltaT = _deltaT;
    if (deltaT <= 0.0)  {
        opserr << "HHTGeneralized_TP::newStep() - error in variable\n";
        opserr << "dT = " << deltaT << endln;
        return -2;
    }
    
    // get a pointer to the LinearSOE and the AnalysisModel
    LinearSOE *theLinSOE = this->getLinearSOE();
    AnalysisModel *theModel = this->getAnalysisModel();
    if (theLinSOE == 0 || theModel == 0)  {
        opserr << "WARNING HHT_TP::newStep() - ";
        opserr << "no LinearSOE or AnalysisModel has been set\n";
        return -3;
    }
    
    // set the constants
    c1 = 1.0;
    c2 = gamma/(beta*deltaT);
    c3 = 1.0/(beta*deltaT*deltaT);
    
    if (U == 0)  {
        opserr << "HHTGeneralized_TP::newStep() - domainChange() failed or hasn't been called\n";
        return -4;
    }
    
    // set weighting factors for subsequent iterations
    alphaM = alphaI;
    alphaD = alphaR = alphaP = alphaF;
    
    // determine new velocities and accelerations at t+deltaT
    double a1 = (1.0 - gamma/beta);
    double a2 = deltaT*(1.0 - 0.5*gamma/beta);
    Udot->addVector(a1, *Utdotdot, a2);
    
    double a3 = -1.0/(beta*deltaT);
    double a4 = 1.0 - 0.5/beta;  
    Udotdot->addVector(a4, *Utdot, a3);
    
    // set the trial response quantities
    theModel->setVel(*Udot);
    theModel->setAccel(*Udotdot);
    
    // increment the time to t+deltaT and apply the load
    double time = theModel->getCurrentDomainTime();
    time += deltaT;
    if (theModel->updateDomain(time, deltaT) < 0)  {
        opserr << "HHTGeneralized_TP::newStep() - failed to update the domain\n";
        return -5;
    }