calc_model_sum2d

sherpa.astro.ui.calc_model_sum2d(reg=None, id: IdType | None = None)

Sum up the convolved model for a 2D data set.

This function is for two-dimensional data sets: use calc_model_sum for one-dimensional data sets.

Parameters:

regstr, optional

The spatial filter to use. The default, None, is to use the whole data set.

idint, str, or None, optional

Use the source expression associated with this data set. If not given then the default identifier is used, as returned by get_default_id.

Returns:

msumnumber

The sum of the model values, as fitted to the data, that lie within the given region. This includes any PSF included by set_psf.

See also

calc_model_sum

Sum up the fitted model over a pass band.

calc_source_sum2d

Sum up the unconvolved model for a 2D data set.

set_psf

Add a PSF model to a data set.

set_model

Set the source model expression for a data set.

Notes

The coordinate system of the region filter is determined by the coordinate setting for the data set (e.g. get_coord).

Any existing filter on the data set - e.g. as created by ignore2d or notice2d - is ignored by this function.

Examples

The following examples use the data in the default data set created with the following calls, which sets the y (data) values to be 0 to 11 in a 3 row by 4 column image:

>>> ivals = np.arange(12)
>>> y, x = np.mgrid[10:13, 20:24]
>>> y = y.flatten()
>>> x = x.flatten()
>>> load_arrays(1, x, y, ivals, (3, 4), DataIMG)
>>> set_source(const2d.bgnd)
>>> bgnd.c0 = 2

with no argument, the full data set is used. Since the model evaluates to 2 per pixel, and there are 12 pixels in the data set, the result is 24:

>>> calc_model_sum2d()
24.0

and a spatial filter can be used to restrict the region used for the summation:

>>> calc_model_sum2d('circle(22,12,1)')
8.0
>>> calc_model_sum2d('field()-circle(22,12,1)')
16.0

Apply the spatial filter to the model for the data set labelled “a2142”:

>>> calc_model_sum2d('rotbox(4232.3,3876,300,200,43)', 'a2142')