Name Type Description constants and global properties Pi real returns 3.14159265358979323846264338328 N int returns N, the total number of bodies M real returns M, the total mass t real returns t, the time of the snapshot #d real parameter number d basic body properties i int returns the index, between 0 and N-1 m real returns the mass pos vector returns the position vector vel vector returns the velocity vector acc vector returns the acceleration vector aux real returns an auxiliary real pot real returns the potential phi real returns the potential eps real returns the individual softening length key int returns the key, an auxiliary integer basic SPH body properties (only with falcON SPH) h real returns the smoothing length, n real returns the number of gas neighbours U real returns the internal energy Ui real returns the (dU/dt)_internal Ue real returns the (dU/dt)_external U real returns the internal energy S real returns the entropy function rho real returns the gas density f real returns the factor f_i s real returns the sound speed components of basic body properties x real returns x, the x-component of pos y real returns y, the y-component of pos z real returns z, the z-component of pos vx real returns vx, the x-component of vel vy real returns vy, the y-component of vel vz real returns vz, the z-component of vel ax real returns ax, the x-component of acc ay real returns ay, the y-component of acc az real returns az, the z-component of acc compounds from basic body properties r real returns abs(pos), the radius R real returns sqrt(x*x+y*y), the cylindrical radius v real returns abs(vel), the total velocity a real returns abs(acc), the total acceleration vr real returns vr, the radial component of vel vt real returns vt, the absolute value of tangential velocity vphi real returns vphi, the azimuthal component of vel l vector returns l=x^v, the specific angular momentum lx real returns Lx, the x-component of l ly real returns Ly, the y-component of l lz real returns Lz, the z-component of l ltot real returns abs(l), the total specific angular momentum jtot real the same as ltot, for NEMO compatibility L vector returns L=l*m, the angular momentum vector Lx real returns Lx, the x-component of L Ly real returns Ly, the y-component of L Lz real returns Lz, the z-component of L Ltot real returns abs(L), the total angular momentum E real returns phi+vel*vel/2, the total energy etot real the same as E, for NEMO compatibility
Name Type Description vector*vector real returns the scalar product vector^vector vector returns the vector cross product vector(x) vector converts scalar to vector real(x) real converts integer to real norm(x) returns x*x for any type abs(vector) real returns sqrt(norm(vector)) abs(real) real returns |real| max(x,y) scalar returns the greater of two scalars max(vector) real returns the greatest vector element min(x,y) scalar returns the smaller of two scalars min(vector) real returns the smallest vector element Compatibilitybodyfunc expressions are backward compatible with bodytrans(5NEMO) expressions, i.e. any valid bodytrans expression may be used. Note, however that bodyfunc allows more functionality, for example vector expressions. ExamplesThe following lists some example bodyfunc expressions expression Type Description r<2 bool true if the radius is less than 2 norm(pos)<#0 bool same as before, but more efficient, since (1) no sqrt() needed and (2) the limit is parametrized E<0? L:vector(zero) vector bound bodies: angular momentum, unbound: 0 See Alsobodyfunc(1falcON), bodytrans(5NEMO) AuthorWalter Dehnen Update History 21-jul-2004 Created WD 07-nov-2004 parameters added, changed cond#expr to expr@cond WD 12-jul-2006 Updated WD