Method eigen

SRC/analysis/analysis/StaticAnalysis.cpp:228–333

int 
StaticAnalysis::eigen(int numMode, bool generalized, bool findSmallest)
{

    if (theAnalysisModel == 0 || theEigenSOE == 0) {
      opserr << "WARNING StaticAnalysis::eigen() - no EigenSOE has been set\n";
      return -1;
    }

    int result = 0;
    Domain *the_Domain = this->getDomainPtr();

    // for parallel processing, want all analysis doing an eigenvalue analysis
    result = theAnalysisModel->eigenAnalysis(numMode, generalized, findSmallest);

    int stamp = the_Domain->hasDomainChanged();

    if (stamp != domainStamp) {
      domainStamp = stamp;
      
      result = this->domainChanged();
      
      if (result < 0) {
	opserr << "StaticAnalysis::eigen() - domainChanged failed";
	return -1;
      }	
    }

    //
    // zero A and M
    //

    theEigenSOE->zeroA();
    theEigenSOE->zeroM();

    //
    // form K
    //

    FE_EleIter &theEles = theAnalysisModel->getFEs();    
    FE_Element *elePtr;

    while((elePtr = theEles()) != 0) {
      elePtr->zeroTangent();
      elePtr->addKtToTang(1.0);
      if (theEigenSOE->addA(elePtr->getTangent(0), elePtr->getID()) < 0) {
	opserr << "WARNING StaticAnalysis::eigen() -";
	opserr << " failed in addA for ID " << elePtr->getID();	    
	result = -2;
      }
    }
   


    // if generalized is true, form M
    //

    if (generalized == true) {