calc_data_sum2d
- sherpa.astro.ui.calc_data_sum2d(reg=None, id=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
reg (str, optional) – The spatial filter to use. The default,
None
, is to use the whole data set.id (int or str, 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
dsum – The sum of the data values that lie within the given region.
- Return type
number
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
ornotice2d
- 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')