CHalo

CHalo
struct CHalo {
long level ;
long mother;
long firstchild;
long nsisters;
long sister;
double rho_saddle;
double density;
double densmax;
double radius ;
double mass ;
double position(3);
// level : integer number corresponding to the level in the tree.
// The root, node(1), corresponds to level=0. The root corresponds
// to all the selected particles (above the density threshold)
// in the simulation box: it is not physically relevant.
// mother : the id of the mother of this node, i.e. the id of substructure
// which contains this substructure (for the root, there is no
// mother, i.e. mother=0).
// firstchild : the id of the first child of this node, i.e. the first
// substructure it contains. Other substructures will be found
// by running over the list their sisters. If we are sitting
// at the end of a branch, firstchild=0 (i.e. this node correspond
// to an elementary substructure) .
// nsisters : the number of sisters of this substructure + 1.
// sister : the id of the sister ``at the right'' of this structure. A structure
// that has not sister at its ``right'' has sister=0.
// rho_saddle : the density of the saddle(s) point(s) connecting this
// structure to its sisters. In principle this could be calculated
// uniquely so that a structure would always have at most one
// sister, but as explained in the important note above,
// rho_saddle is computed approximately, as a result, it can
// correspond to more than a single saddle point.
// For a given density threshold, rho_th, if rho_th > rho_saddle,
// the substructure is connected to its sisters, whereas if
// rho_th < rho_saddle, the substructure is disconnected from its
// sisters.
// density : average density of the substructure, calculated from the
// average SPH density of all particles with SPH density larger than
// rho_saddle and belonging to the substructure.
// densmax : maximum density within the substructure : it correspond
// to the largest SPH density of all the particles within the
// substructure.
// radius : size in Mpc of the substructure calculated by computing the mean
// square distance of each particle belonging to it with respect
// to its center of mass.
// mass : number of particles within the substructure.
// position(3) : coordinates in Mpc of the center of mass of the
// substructure.
}
