Rebuild an orbit_system from a simulation snapshot

Takes the state of every body at one time step of a simulation and returns a new `orbit_system` with those positions and velocities as its initial conditions. This is the bridge from a finished run back to a system you can modify (add a body, remove one, change a velocity) and simulate again.

Usage

system_from_simulation(sim_data, time = NULL, G = NULL)

Arguments

sim_data

A tibble output from [simulate_system()].

time

The simulation time (in seconds) of the snapshot to use. Defaults to the last time step. Snaps to the closest available time.

G

The gravitational constant for the new system. Defaults to the value recorded by [simulate_system()] in the `"G"` attribute of `sim_data`, or to [gravitational_constant] if that is absent.

Value

An `orbit_system` whose bodies have the snapshot's positions and velocities.

Examples

# \donttest{
sim <- create_system() |>
  add_sun() |>
  add_planet("Earth", parent = "Sun") |>
  simulate_system(time_step = seconds_per_day, duration = seconds_per_day * 100)

# Where everything was on day 100, as a system ready to simulate again
later <- system_from_simulation(sim)
later
#> ───────────────────────────────── orbit_system ───────────────────────────────── 
#> G: 6.6743e-11 (standard)
#> Bodies: 2
#> 
#> # A tibble: 2 × 8
#>   id       mass        x             y     z        vx          vy    vz
#>   <chr>   <dbl>    <dbl>         <dbl> <dbl>     <dbl>       <dbl> <dbl>
#> 1 Sun   1.99e30 -4.51e 5       433299.     0    -0.123      0.0620     0
#> 2 Earth 5.97e24 -1.38e11 -59601314664.     0 11348.    -27451.         0
# }