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:	(float or array (K) – 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

radvel.utils.working_directory(dir)[source]¶

Do something in a directory

Function to use with with statements.

Parameters:	dir (string) – name of directory to work in

Example

>>> with workdir('/temp'):
    # do something within the /temp directory