guess_radius

sherpa.utils.guess_radius(x0lo, x1lo, x0hi=None, x1hi=None)

Guess the radius parameter of a 2D model.

Parameters:

• x1lo (x0lo,) – The independent axes of the grid, in 1D form.
• x1hi (x0hi,) – The upper bounds of each pixel.

Returns:

ans – The keys are ‘val’, ‘min’, and ‘max’, which give the radius and its range, in units of the input grid (x0lo and x1lo).

Return type:

dict

Notes

Currently only x0lo is used, and it is assumed to be arranged so that this axis varies fastest (that is x0lo[1] > x0lo[0]) as well as representing square pixels of the same size.

The scaling factor for the minimum and maximum values is taken from the module’s _guess_ampl_scale variable.