pynbody.derived

Functions that derive arrays (e.g. radius) from others (e.g. position)

Users do not need to call these functions directly. They are called automatically when a derived array is requested from any SimSnap.

See also

Not all derived arrays that are provided by the pynbody framework are defined in this module. In particular, see luminosity for arrays related to stellar luminosity.

For more information about how the derived array system operates, see Automatically Derived Arrays.

Functions

aform(self)	Derived: The expansion factor at the time specified by the tform array.
age(self)	Derived: Stellar age determined from formation time and current snapshot time
alt(self)	Derived: Angle from the horizon, from [-pi/2:pi/2]
az(self)	Derived: Angle in the xy plane from the x axis, from [-pi:pi]
cs(self)	Derived: Sound speed
iord_argsort(self)	Derived: Indices so that particles are ordered by increasing ids
j(self)	Derived: Specific angular momentum
j2(self)	Derived: Square of the specific angular momentum
jz(self)	Derived: z-component of the angular momentum
ke(self)	Derived: Specific kinetic energy
mu(sim[, t0, Y])	Derived: Mean molecular mass, i.e. the mean atomic mass per particle.
p(sim)	Derived: Pressure
r(self)	Derived: Radial position
rxy(self)	Derived: Cylindrical radius in the x-y plane
te(self)	Derived: Specific total energy
temp(self)	Derived: Gas temperature derived from internal energy
tform(self)	Derived: The time of the specified expansion factor in the aform
theta(self)	Derived: Angle from the z axis, from [0:pi]
u(self)	Derived: Gas internal energy derived from temperature
v2(self)	Derived: Squared velocity
v_curl(self)	Derived: SPH-smoothed curl of velocity
v_disp(self)	Derived: SPH-smoothed velocity dispersion
v_div(self)	Derived: SPH-smoothed divergence of velocity
v_mean(self)	Derived: SPH-smoothed mean velocity
vcxy(self)	Derived: Cylindrical tangential velocity in the x-y plane
vorticity(self)	Derived: SPH-smoothed vorticity
vphi(self)	Derived: Azimuthal velocity (synonym for vcxy)
vr(self)	Derived: Radial velocity
vrxy(self)	Derived: Cylindrical radial velocity in the x-y plane
vt(self)	Derived: Tangential velocity
vtheta(self)	Derived: Velocity projected to polar direction
zeldovich_offset(self)	Derived: The position offset in the current snapshot according to the Zel'dovich approximation applied to the current velocities.