ki_and_variance_grid

romanisim.ramp.ki_and_variance_grid(read_pattern, flux_on_readvar_pts)

Construct a grid of \(k\) and covariances for the values of flux_on_readvar.

The \(k\) and corresponding covariances needed to do ramp fitting form essentially a one dimensional family in the flux in the ramp divided by the square of the read noise. This function constructs these quantities for a large number of different flux / read_noise^2 to be used in interpolation.

Parameters:

read_patternlist[list] (int)

a list of lists of the indices of the reads entering each resultant

flux_on_readvar_ptsarray_like (float)

values of flux / read_noise**2 for which \(k\) and variances are desired.

Returns:

kigridnp.ndarray[len(flux_on_readvar_pts), 2, n_resultants] (float)

\(k\) for each value of flux_on_readvar_pts

vargridnp.ndarray[len(flux_on_readvar_pts), n_covar, 2, 2] (float)

covariance of pedestal and slope corresponding to each value of flux_on_readvar_pts. n_covar = 3, for the contributions from read_noise, Poisson noise, and the sum.