//*************************************************************
void fitter::ComputeSeed(const Trajectory& traj, State& seedState, int firsthit) {
//*************************************************************
_m.message("+++ computeSeed function ++++",bhep::VERBOSE);
//use position slightly offset from first meas as seed
///_lastIso is the total no of candidate muon hits inside Traj in free section
if ( (double)(traj.quality("lastIso"))/(double)traj.size() > _min_iso_prop )
firsthit = (int)traj.size() - (int)(traj.quality("lastIso"));
EVector v(6,0), v2(1,0);
EMatrix C(6,6,0), C2(1,1,0);
// take the position from the first hit
v[0] = traj.nodes()[firsthit]->measurement().position()[0];
v[1] = traj.nodes()[firsthit]->measurement().position()[1];
v[2] = traj.nodes()[firsthit]->measurement().position()[2];
// Estime the momentum from range
ComputeMomFromRange( traj, (int)traj.size(), firsthit, v);
double pSeed;
double wFe = _geom.get_Fe_prop();
//Approximate p from plot of p vs. no. hits, then approx. de_dx from this.
if (v[5] == 0) { //pSeed = (double)(0.060*traj.nmeas())*bhep::GeV;
pSeed = (13300-11200*wFe) + (-128+190*wFe)*(double)traj.size();
v[5] = 1.0/pSeed;
}
// But use a larger covariance matrix
// diagonal covariance matrix
C[0][0] = C[1][1] = 9.*cm*cm;
C[2][2] = EGeo::zero_cov()/2;
C[3][3] = C[4][4] = 1.;
C[5][5] = pow(v[5],2)*3;
// seedState.set_name(RP::particle_helix);
seedState.set_name(RP::representation,RP::slopes_curv_z);
v2[0] = 1;
seedState.set_hv(RP::sense,HyperVector(v2,C2,RP::x));
seedState.set_hv(HyperVector(v,C,RP::slopes_curv_z));
_m.message("++ Seed estate after setSeed() in fitter:",seedState,bhep::VERBOSE);
}
