Useful Functions

Miscellaneous useful auxiliary functions:

pyimfit.get_function_list()

Returns a list of Imfit image-function names (e.g., [“Gaussian”, “Exponential”, etc.])

Returns:

function_list – list of Imfit image-function names

Return type:

list of str

pyimfit.get_function_dict()

Returns a dict mapping each Imfit image-function names to a list of its corresponding parameter names.

Returns:

function_dict – dict where image-function names are keys and items are list of function parameter names

Return type:

dict

pyimfit.make_imfit_function(func_type, label='')

Given a string specifying the official name of an Imfit image function (e.g., “Sersic”, “Sersic_GenEllipse”, “ExponentialDisk3D”), this returns an instance of FunctionDescription describing that function and its parameters (with values all set to 0).

Parameters:

  • func_type (string) – The function type; must be one of the recognized Imfit image-function names (E.g., “Sersic”, “BrokenExponential”, etc. Use “imfit –list-functions” on the command line to get the full list, or FunctionNames in this module.)

  • label (string, optional) – Custom identifying label for this instance of this function. Example: “disk”, “bulge”. Default: “” (which means no label).

Returns:

func_desc – Instance of FunctionDescription.

Return type:

FunctionDescription

pyimfit.parse_config_file(fileName: str) → ModelDescription

Read and parse an Imfit model-configuration file.

Parameters:

fileName (str) – Path to the model configuration file.

Returns:

  • model (ModelDescription) – A model description object.

  • See Imfit documentation for details on the format of configuration files.

pyimfit.parse_config(lines: List[str]) → ModelDescription

Parse an Imfit model configuration from a list of strings.

Parameters:

lines (list of str) – String representantion of Imfit model configuration.

Returns:

model – A model description object.

Return type:

ModelDescription

See also

parse_config_file

pyimfit.MakePsfOversampler(psfImage, oversampleScale, regionSpec, psfNormalization=True)

Helper function to generate PsfOversampling objects (corrects input psfImage, sets up region string, etc.).

Parameters:

  • psfImage (2-D numpy array) – the oversampled PSF image

  • oversampleScale (int) –

    oversampling scale of psfImage relative to data image: number of PSF-image

    pixels per data-image pixel in one dimension (must be >= 1)

  • regionSpec (sequence of int) – specifies inclusive boundaries of image region to be oversampled [x1,x2,y1,y2]

  • psfNormalization (bool, optional) – Normalize the PSF image before using. Default: True.

Returns:

oversampleInfo

Return type:

instance of PsfOversampling class

pyimfit.FixImage(array)

Checks an input numpy array and, if necessary, converts it to double-precision floating point, little-endian byte order, with contiguous layout, to enable use with Imfit.

Parameters:

array (numpy ndarray) –

Returns:

array – The input array, suitably converted

Return type:

numpy ndarray