Method getLambdaSensitivity

SRC/analysis/integrator/DisplacementControl.cpp:794–837

dLambdadh of the subsequent iterations (J>1)

 // dLambdadh of the subsequent iterations (J>1)
double 
DisplacementControl::getLambdaSensitivity(int gradNumber)
{

  //call the tangent displacement component (deltaUhat)
  // LinearSOE *theLinSOE = this->getLinearSOE(); 

  //  this->formTangent();
  //  theLinSOE->setB(*phat);
  //   if (theLinSOE->solve() < 0) {
  //      opserr << "DisplacementControl::newStep(void) - failed in solver\n";
  //      return -1;
  //   }

  //  (*deltaUhat) = theLinSOE->getX();
 
   Vector &UFT=*deltaUhat;
   double UFT_Comp=UFT(theDofID);

   //call the derivative of the tangent displacement component (dUftdh).
   Vector &duHatdh=*dUhatdh;
   double duHatdh_Comp=duHatdh(theDofID);

   //Call the residual displacement component
   Vector &dufR=*deltaUbar;
   double dufR_Comp=dufR(theDofID);

   Vector &dufRdh=*dUIJdh;// component of the dUfrDh: derivative of the residual displacement
   double dufRdh_Comp=dufRdh(theDofID);

   if(UFT_Comp==0.0 )
     Dlambdadh=0.0;
   else
     // dLambdadh_ij( the sensitivity of the load component to the parameter h)
     Dlambdadh=((-dufRdh_Comp*UFT_Comp  +(dufR_Comp*duHatdh_Comp)))/(UFT_Comp*UFT_Comp);  //   
 
   // Now update Lambda_ij
   if(dLAMBDAdh !=0) {
     (*dLAMBDAdh)(gradNumber) = (*dLAMBDAdh)(gradNumber)+ Dlambdadh;
     return (*dLAMBDAdh)(gradNumber);
   } else {
     return 0.0;
   }
}