void multiRootSolver<scalarT,dim>::backTrack(value_type farPoint, value_type farValue){
real_type stepSize=(this->z-farPoint).norm();
#if DEBUG>=STATUS
cout << __FILE__ << " : back tracking"<<endl;
#endif
real_type farAbsF = farValue.norm();
real_type change = this->absF - farAbsF;
if(change!=change){//nan
throw runtime_error(string(__FILE__) + string(" : Error in function evaluation!"));
}
#if DEBUG>=DETAIL
cout << __FILE__ << " : step size " << stepSize << " leads to absF improvement: " <<change <<endl;
#endif
this->state = this->checkStatus(farAbsF, this->absF, stepSize);
// simple backtracking
if(this->state==REJECT){
value_type newFarPoint = 0.5 * (farPoint + this->z);
this->calc->changePoint(newFarPoint);
backTrack(newFarPoint, this->calc->calcF());
}else{
lastAbsValueChange=change;
this->f=farValue;
this->absF=farAbsF;
absLastStep=stepSize;
this->z=farPoint;
calculatedJ=false;
}
}
