Results

class orbitize.results.Results(sampler_name=None, post=None, lnlike=None, tau_ref_epoch=None, labels=None, num_secondary_bodies=None)[source]

A class to store accepted orbital configurations from the sampler

Parameters

  • sampler_name (string) – name of sampler class that generated these results (default: None).

  • post (np.array of float) – MxN array of orbital parameters (posterior output from orbit-fitting process), where M is the number of orbits generated, and N is the number of varying orbital parameters in the fit (default: None).

  • lnlike (np.array of float) – M array of log-likelihoods corresponding to the orbits described in post (default: None).

  • tau_ref_epoch (float) – date (in days, typically MJD) that tau is defined relative to

  • labels (list of str) – parameter labels in same order as post

  • num_secondary_bodies (int) – number of companions fit

The post array is in the following order:

semimajor axis 1, eccentricity 1, inclination 1,
argument of periastron 1, position angle of nodes 1,
epoch of periastron passage 1,
[semimajor axis 2, eccentricity 2, etc.],
[parallax, masses (see docstring for orbitize.system.System)]

where 1 corresponds to the first orbiting object, 2 corresponds to the second, etc.

Written: Henry Ngo, Sarah Blunt, 2018

add_samples(orbital_params, lnlikes, labels)[source]

Add accepted orbits and their likelihoods to the results

Parameters

  • orbital_params (np.array) – add sets of orbital params (could be multiple) to results

  • lnlike (np.array) – add corresponding lnlike values to results

  • labels (list of str) – list of parameter labels specifying the order in orbital_params

Written: Henry Ngo, 2018

load_results(filename, append=False)[source]

Populate the results.Results object with data from a datafile

Parameters

  • filename (string) – filepath where data is saved

  • append (boolean) – if True, then new data is added to existing object. If False (default), new data overwrites existing object

See the save_results() method in this module for information on how the data is structured.

Written: Henry Ngo, 2018

plot_corner(param_list=None, **corner_kwargs)[source]

Make a corner plot of posterior on orbit fit from any sampler

Parameters

  • param_list (list of strings) –

    each entry is a name of a parameter to include. Valid strings:

    sma1: semimajor axis
ecc1: eccentricity
inc1: inclination
aop1: argument of periastron
pan1: position angle of nodes
tau1: epoch of periastron passage, expressed as fraction of orbital period
[repeat for 2, 3, 4, etc if multiple objects]
plx:  parallax
gamma: rv offset
sigma: rv jitter
mi: mass of individual body i, for i = 0, 1, 2, ... (only if fit_secondary_mass == True)
mtot: total mass (only if fit_secondary_mass == False)

  • **corner_kwargs – any remaining keyword args are sent to corner.corner. See here. Note: default axis labels used unless overwritten by user input.

Returns

corner plot

Return type

matplotlib.pyplot.Figure

Note

Example: Use param_list = ['sma1,ecc1,inc1,sma2,ecc2,inc2'] to only plot posteriors for semimajor axis, eccentricity and inclination of the first two companions

Written: Henry Ngo, 2018

plot_orbits(object_to_plot=1, start_mjd=51544.0, num_orbits_to_plot=100, num_epochs_to_plot=100, square_plot=True, show_colorbar=True, cmap=<matplotlib.colors.LinearSegmentedColormap object>, sep_pa_color='lightgrey', sep_pa_end_year=2025.0, cbar_param='epochs', mod180=False, rv_time_series=False)[source]

Plots one orbital period for a select number of fitted orbits for a given object, with line segments colored according to time

Parameters

  • object_to_plot (int) – which object to plot (default: 1)

  • start_mjd (float) – MJD in which to start plotting orbits (default: 51544, the year 2000)

  • num_orbits_to_plot (int) – number of orbits to plot (default: 100)

  • num_epochs_to_plot (int) – number of points to plot per orbit (default: 100)

  • square_plot (Boolean) – Aspect ratio is always equal, but if square_plot is True (default), then the axes will be square, otherwise, white space padding is used

  • show_colorbar (Boolean) – Displays colorbar to the right of the plot [True]

  • cmap (matplotlib.cm.ColorMap) – color map to use for making orbit tracks (default: modified Purples_r)

  • sep_pa_color (string) – any valid matplotlib color string, used to set the color of the orbit tracks in the Sep/PA panels (default: ‘lightgrey’).

  • sep_pa_end_year (float) – decimal year specifying when to stop plotting orbit tracks in the Sep/PA panels (default: 2025.0).

  • cbar_param (string) – options are the following: epochs, sma1, ecc1, inc1, aop1, pan1, tau1. Number can be switched out. Default is epochs.

  • mod180 (Bool) – if True, PA will be plotted in range [180, 540]. Useful for plotting short arcs with PAs that cross 360 deg during observations (default: False)

  • rv_time_series (Boolean) – if fitting for secondary mass using MCMC for rv fitting and want to display time series, set to True.

Returns

the orbit plot if input is valid, None otherwise

Return type

matplotlib.pyplot.Figure

(written): Henry Ngo, Sarah Blunt, 2018 Additions by Malena Rice, 2019

save_results(filename)[source]

Save results.Results object to an hdf5 file

Parameters

filename (string) – filepath to save to

Save attributes from the results.Results object.

sampler_name, tau_ref_epcoh are attributes of the root group. post, lnlike, and parameter_labels are datasets that are members of the root group.

Written: Henry Ngo, 2018