calc_data_sum2d

sherpa.astro.ui.calc_data_sum2d(reg=None, id: IdType | None = None)

Sum up the data values of 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:

dsumnumber

The sum of the data values that lie within the given region.

See also

calc_data_sum

Sum up the data values of a data set.

calc_model_sum2d

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

calc_source_sum2d

Sum up the unconvolved model for a 2D 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)

with no argument, the full data set is used:

>>> calc_data_sum2d()
66
>>> ivals.sum()
66

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

>>> calc_data_sum2d('circle(22,12,1)')
36
>>> calc_data_sum2d('field()-circle(2,2,1)')
30

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

>>> calc_data_sum2d('rotbox(4232.3,3876,300,200,43)', 'a2142')