misc

Small miscellaneous helpers used in examples and notebooks.

Full API

Small miscellaneous helpers used in examples and notebooks.

The utilities here are lightweight helpers that operate on the simple file structures used across the dorito examples (for example calslope-like objects) and a couple of geometry helpers used when building model inputs.

truncate_files(files, ngroups)

Truncate the ramp of files to only have ngroups. This is use for saturated or highly nonlinear data where you want to discard the top of the ramp.

This modifies the list of file-like objects in-place by trimming the top groups from the arrays stored under keys like RAMP / SLOPE and their covariance counterparts.

Parameters:

Name	Type	Description	Default
files	list	Sequence of file-like objects where attributes such as RAMP and SLOPE provide .data arrays whose first axis indexes groups.	required
ngroups	int	Number of groups to preserve at the start of the ramp.	required

Source code in src/dorito/misc.py

def truncate_files(files, ngroups):
    """Truncate the ramp of files to only have ngroups. This is use for
    saturated or highly nonlinear data where you want to discard the top of
    the ramp.

    This modifies the list of file-like objects in-place by trimming the top
    groups from the arrays stored under keys like ``RAMP`` / ``SLOPE`` and
    their covariance counterparts.

    Parameters
    ----------
    files : list
        Sequence of file-like objects where attributes such as ``RAMP`` and
        ``SLOPE`` provide ``.data`` arrays whose first axis indexes groups.
    ngroups : int
        Number of groups to preserve at the start of the ramp.
    """

    for file in files:

        # grabbing the total number of groups in the ramp
        top_group = file["RAMP"].data.shape[0]
        up_to = top_group - ngroups

        # files are mutable, so they will change in place
        for attr in ["RAMP", "SLOPE", "RAMP_SUP", "SLOPE_SUP"]:
            file[attr].data = file[attr].data[:-up_to, ...]
        for attr in ["RAMP_COV", "SLOPE_COV"]:
            file[attr].data = file[attr].data[:-up_to, :-up_to, ...]

fwhm_to_sigma(fwhm)

Convert FWHM to sigma for a Gaussian distribution.

Parameters:

Name	Type	Description	Default
fwhm	float	Full width at half maximum.	required

Returns:

Type	Description
float	Corresponding standard deviation (sigma).

Source code in src/dorito/misc.py

def fwhm_to_sigma(fwhm):
    """
    Convert FWHM to sigma for a Gaussian distribution.

    Parameters
    ----------
    fwhm : float
        Full width at half maximum.
    Returns
    -------
    float
        Corresponding standard deviation (sigma).
    """
    return fwhm / (2 * np.sqrt(2 * np.log(2)))

calc_parang(file)

Return the parallactic/roll angle extracted from a file header.

Parameters:

Name	Type	Description	Default
file	mapping - like	File-like object with a PRIMARY header containing ROLL_REF.	required

Returns:

Type	Description
ndarray	Numeric parallactic/roll angle.

Source code in src/dorito/misc.py

def calc_parang(file):
    """Return the parallactic/roll angle extracted from a file header.

    Parameters
    ----------
    file : mapping-like
        File-like object with a ``PRIMARY`` header containing ``ROLL_REF``.

    Returns
    -------
    ndarray
        Numeric parallactic/roll angle.
    """
    return np.array(file["PRIMARY"].header["ROLL_REF"])