subroutine kvtx_fixed_2d(ntrk, list_trk, update_tracks, vertex, * chisq, error) * * begin_doc * * Fit several tracks to pass through a fixed point. Only the r-phi * constraint is used. * * Input Parameters: * ntrk integer variable * # of tracks to fit (length of list_trk) * * list_trk(*) integer array * List of tracks in track list to fit (length = ntrk) * * update_tracks integer variable * 0 ==> don't update input track parameters * 1 ==> update input track parameters * 2 ==> update input track parameters & covariance matrices * and replace the original unconstrainted parameters * by the new ones. * * vertex(3) double precision array * (x,y,z) of point (z is ignored) * * Output Parameters: * chisq double precision variable * Chisquare of fit * * error integer variable * 0 if all OK * >0 if error * * Other routines: * * Notes: * * Author: Paul Avery Created: Wed Aug 20 14:58:50 EDT 1997 * * Major revisions: * * * end_doc