PEPITA Documentation
The exoInfoMatrix
class
- class pepita.exoInfoMatrix.exoInfoMatrix(exptime, oversample=100)[source]
Bases:
object
Information Analysis Matrix class.
To initalize, use the exposure time (cadence) of the lightcurve in seconds. For example:
info_matrix = exoInfoMatrix(20) # 20 second cadence
Then define the parameters of the fiducial model
- info_matrix.set_data(
time_array, period_val, t0_val, ror_val, b_val, u1_val, u2_val, m_star_val, r_star_val, )
To calculate the covariance matrix, passing the error of the measurements into it
cov_matrix = info_matrix.eval_cov(sigma)
- eval_cov(sigma=None)[source]
Used to evaluate the covariance matrix
- Parameters:
sigma (float or array) – Error in the flux measurements. Either a single float value to be used for all points or an array of size len(time_array) with individual errors for each timestamps
- Returns:
Covariance matrix
- Return type:
array
- eval_deriv_matrix()[source]
Evaluates the matrix of derivatives for all timestamps in time_array
- Returns:
Matrix of derivatives
- Return type:
array
- Raises:
ValueError – If fiducial model parameters have not been defined
- eval_fisher(sigma)[source]
Used to evaluate the information matrix
- Parameters:
sigma (float or array) – Error in the flux measurements. Either a single float value to be used for all points or an array of size len(time_array) with individual errors for each timestamps
- Returns:
Information matrix
- Return type:
array
- eval_point(tval)[source]
Evaluates the derivatives at a given point
- Parameters:
tval (float) – Time at which to evaluate the derivatives, in same units as time_array
- Returns:
array of derivatives
- Return type:
array
- Raises:
ValueError – If values of the fiducial model have not been set.
- get_approx_transit_duration(n_points=10000)[source]
Approximate the duration of the transit. Not efficient and used only for testing purposes
- Parameters:
n_points (int, optional) – number of points for calculating appproximation, by default 10000
- Returns:
Approximate duration of the transit
- Return type:
float
- get_in_transit()[source]
Get the number of data points which are in-transit
- Returns:
Number of points in transit
- Return type:
int
- plot_derivs(fig_ax=None)[source]
Plots the derivatives of the transit model.
- Parameters:
fig_ax ((figure, axes), optional) – If derivatives should be plotted in given figure and axes. Note that this is meant to be used for plotting different model derivatives on top of eachother and so (figure, axis) should be the output of calling plot_derivs() in other model.
- Returns:
figure and axes
- Return type:
(figure, axes)
- setExptime(exptime)[source]
Changes the exposure time (cadence) of the model. Will force redefinition of parameters
- Parameters:
exptime (float) – The new cadence in seconds.
- set_data(time_array, period_val, t0_val, ror_val, b_val, u1_val, u2_val, m_star_val, r_star_val)[source]
Set the data for the fiducial model. The fiducial model is used to evaluate the derivatives and can be a first approximation of the planet parameters from the maximum likelihood set of parameters or from previous fits.
- Parameters:
time_array (array[float]) – Timestamps of the lightcurve. In days.
period_val (float) – Period of the planet in days
t0_val (float) – Reference time for the middle of one of the planet transits. In days.
ror_val (float) – Radius ratio of the planet and star
b_val (float) – Impact parameter of the planet
u1_val (float) – First limb-darkening parameter for a quadratic limb-darkening model
u2_val (float) – Second limb-darkening parameter for a quadratic limb-darkening model
m_star_val (float) – Mass of the star in solar masses
r_star_val (float) – Radius of star in solar radii
- set_priors(period_prior=nan, t0_prior=nan, ror_prior=nan, b_prior=nan, u1_prior=nan, u2_prior=nan, m_star_prior=nan, r_star_prior=nan)[source]
Used to define priors for the parameters
- Parameters:
period_prior (float) – Prior for planet period in days
t0_prior (float) – Prior for t0 in days
ror_prior (float) – Prior for planet ratio
b_prior (float) – Prior for impact parameter
u1_prior (float) – Prior for first quadratic limb darkening parameter
u2_prior (float) – Prior for second quadratic limb darkening parameter
m_star_prior (float) – Prior for mass of the star
r_star_prior (float) – Prior for radius of the star
- Returns:
Priors matrix
- Return type:
array