Utility Functions
- radvel.utils.Msini(K, P, Mstar, e, Msini_units='earth')[source]
Calculate Msini
Calculate Msini for a given K, P, stellar mass, and e
- Parameters
array (K (float or) – Doppler semi-amplitude [m/s]
P (float or array) – Orbital period [days]
Mstar (float or array) – Mass of star [Msun]
e (float or array) – eccentricity
Msini_units (Optional[str]) – Units of Msini {‘earth’,’jupiter’} default: ‘earth’
- Returns
Msini [units = Msini_units]
- Return type
float or array
- radvel.utils.bintels(t, vel, err, telvec, binsize=0.5)[source]
Bin velocities by instrument
Bin RV data with bins of with binsize in the units of t. Will not bin data from different telescopes together since there may be offsets between them.
- Parameters
t (array) – array of timestamps
vel (array) – array of velocities
err (array) – array of velocity uncertainties
telvec (array) – array of strings corresponding to the instrument name for each velocity
binsize (float) – (optional) width of bin in units of t (default=1/2.)
- Returns
(bin centers, binned measurements, binned uncertainties, binned instrument codes)
- Return type
tuple
- radvel.utils.date2jd(date)[source]
Convert datetime object to JD”
- Parameters
date (datetime.datetime) – date to convert
- Returns
Julian date
- Return type
float
- radvel.utils.density(mass, radius, MR_units='earth')[source]
Compute density from mass and radius
- Parameters
mass (float) – mass [MR_units]
radius (float) – radius [MR_units]
MR_units (string) – (optional) units of mass and radius. Must be ‘earth’, or ‘jupiter’ (default ‘earth’).
- Returns
density in g/cc
- Return type
float
- radvel.utils.draw_models_from_chain(mod, chain, t, nsamples=50)[source]
Draw Models from Chain
Given an MCMC chain of parameters, draw representative parameters and synthesize models.
- Parameters
mod (radvel.RVmodel) – RV model
chain (DataFrame) – pandas DataFrame with different values from MCMC chain
t (array) – time range over which to synthesize models
nsamples (int) – number of draws
- Returns
2D array with the different models as different rows
- Return type
array
- radvel.utils.fastbin(x, y, nbins=30)[source]
Fast binning
Fast binning function for equally spaced data
- Parameters
x (array) – independent variable
y (array) – dependent variable
nbins (int) – number of bins
- Returns
(bin centers, binned measurements, binned uncertainties)
- Return type
tuple
- radvel.utils.geterr(vec, angular=False)[source]
Calculate median, 15.9, and 84.1 percentile values for a given vector.
- Parameters
vec (array) – vector, usually an MCMC chain for one parameter
angular (bool [optioanl]) – Is this an angular parameter? if True vec should be in radians. This will perform some checks to ensure proper boundary wrapping.
- Returns
50, 15.9 and 84.1 percentiles
- Return type
tuple
- radvel.utils.initialize_posterior(config_file, decorr=False)[source]
Initialize Posterior object
Parse a setup file and initialize the RVModel, Likelihood, Posterior and priors.
- Parameters
config_file (string) – path to config file
decorr (bool) – (optional) decorrelate RVs against columns defined in the decorr_vars list
- Returns
(object representation of config file, radvel.Posterior object)
- Return type
tuple
- radvel.utils.jd2date(jd)[source]
Convert JD to datetime.datetime object
- Parameters
jd (float) – Julian date
- Returns
calendar date
- Return type
datetime.datetime
- radvel.utils.load_module_from_file(module_name, module_path)[source]
Loads a python module from the path of the corresponding file.
- Parameters
module_name (str) – namespace where the python module will be loaded, e.g.
foo.bar
module_path (str) – path of the python file containing the module
- Returns
A valid module object
- Raises
ImportError – when the module can’t be loaded
FileNotFoundError – when module_path doesn’t exist
- radvel.utils.round_sig(x, sig=2)[source]
Round by significant figures :param x: number to be rounded :type x: float :param sig: (optional) number of significant figures to retain :type sig: int
- Returns
x rounded to sig significant figures
- Return type
float
- radvel.utils.semi_amplitude(Msini, P, Mtotal, e, Msini_units='jupiter')[source]
Compute Doppler semi-amplitude
- Parameters
Msini (float) – mass of planet [Mjup]
P (float) – Orbital period [days]
Mtotal (float) – Mass of star + mass of planet [Msun]
e (float) – eccentricity
Msini_units (Optional[str]) – Units of Msini {‘earth’,’jupiter’} default: ‘jupiter’
- Returns
Doppler semi-amplitude [m/s]
- radvel.utils.semi_major_axis(P, Mtotal)[source]
Semi-major axis
Kepler’s third law
- Parameters
P (float) – Orbital period [days]
Mtotal (float) – Mass [Msun]
- Returns
semi-major axis in AU
- Return type
float or array
- radvel.utils.sigfig(med, errlow, errhigh=None)[source]
Format values with errors into an equal number of signficant figures.
- Parameters
med (float) – median value
errlow (float) – lower errorbar
errhigh (float) – upper errorbar
- Returns
(med,errlow,errhigh) rounded to the lowest number of significant figures
- Return type
tuple
- radvel.utils.t_to_phase(params, t, num_planet, cat=False)[source]
Time to phase
Convert JD to orbital phase
- Parameters
params (radvel.params.RVParameters) – RV parameters object
t (array) – JD timestamps
num_planet (int) – Which planet’s ephemeris to phase fold on
cat (bool) – Concatenate/double the output phase array to extend from 0 to 2
- Returns
orbital phase at each timestamp
- Return type
array
- radvel.utils.time_print(tdiff)[source]
Print time
Helper function to print time remaining in sensible units.
- Parameters
tdiff (float) – time in seconds
- Returns
(float time, string units)
- Return type
tuple
- radvel.utils.timebin(time, meas, meas_err, binsize)[source]
Bin in equal sized time bins
This routine bins a set of times, measurements, and measurement errors into time bins. All inputs and outputs should be floats or double. binsize should have the same units as the time array. (from Andrew Howard, ported to Python by BJ Fulton)
- Parameters
time (array) – array of times
meas (array) – array of measurements to be comined
meas_err (array) – array of measurement uncertainties
binsize (float) – width of bins in same units as time array
- Returns
(bin centers, binned measurements, binned uncertainties)
- Return type
tuple