Trajectory results

Trajectory results are simply a vehicle to output full trajectories of tracers (even though they are never stored in memory over the full cosmic time). The user can choose whether to output only radial information or also full 3D positions and velocities. As trajectory information quickly becomes very large, this result should typically only be switched on for one or a few halos (see Run-time configuration parameters for how to set such instructions).

Compile-time parameters

Parameter	Explanation
OUTPUT_RESULT_TRAJECTORY	Write trajectory results to output file
OUTPUT_RESULT_TRAJECTORY_R	Save the tracer’s radius along the trajectory
OUTPUT_RESULT_TRAJECTORY_VR	Save the tracer’s radial velocity along the trajectory
OUTPUT_RESULT_TRAJECTORY_VT	Save the tracer’s tangential velocity along the trajectory
OUTPUT_RESULT_TRAJECTORY_X	Save the tracer’s full 3-dimensional coordinates along the trajectory
OUTPUT_RESULT_TRAJECTORY_V	Save the tracer’s full 3-dimensional velocity along the trajectory

Run-time parameters

This result does not add any config parameters.

Output fields

Field	Type	Dimensions	Exists if	Explanation
halo_first	int64	n_halos	Always	The index of the first result for each halo (or -1 if none exists for a halo).
halo_n	int32	n_halos	Always	The number of results of this type for each halo (can be 0).
tracer_id	int64	n_rs_trajectory	Always	The ID of the tracer to which this result refers.
first_snap	int16	n_rs_trajectory	Always	The first snapshot where the trajectory was recorded.
last_snap	int16	n_rs_trajectory	Always	The last snapshot where the trajectory was recorded.
r	float	n_rs_trajectory * 3	OUTPUT_RESULT_TRAJECTORY_R	The radius of the tracer as a function of time.
vr	float	n_rs_trajectory * 3	OUTPUT_RESULT_TRAJECTORY_VR	The radial velocity as a function of time.
vt	float	n_rs_trajectory * 3	OUTPUT_RESULT_TRAJECTORY_VT	The tangential velocity as a function of time.
x	float	n_rs_trajectory * 3	OUTPUT_RESULT_TRAJECTORY_X	The relative coordinates as a function of time; r is implicit in this field.
v	float	n_rs_trajectory * 3	OUTPUT_RESULT_TRAJECTORY_V	The relative velocity as a function of time; vr is implicit in this field.