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AHELP for CIAO 4.13 Sherpa v1

# calc_data_sum2d

Context: utilities

## Synopsis

Sum up the data values of a 2D data set.

## Syntax

```calc_data_sum2d(reg=None, id=None)

reg - str, optional
id - int or str, optional```

## Description

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

## Examples

### Example 1

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```

### Example 2

Apply the spatial filter to the data set labelled "a2142":

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

### PARAMETERS

The parameters for this function are:

Parameter Definition
reg The spatial filter to use. The default, none , is to use the whole data set.
id Use the source expression associated with this data set. If not given then the default identifier is used, as returned by `get_default_id` .

### Return value

The return value from this function is:

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

### 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.

## Bugs

See the bugs pages on the Sherpa website for an up-to-date listing of known bugs.

data
copy_data, dataspace1d, dataspace2d, datastack, delete_data, fake, get_axes, get_bkg_chisqr_plot, get_bkg_delchi_plot, get_bkg_fit_plot, get_bkg_model_plot, get_bkg_plot, get_bkg_ratio_plot, get_bkg_resid_plot, get_bkg_source_plot, get_counts, get_data, get_data_contour, get_data_contour_prefs, get_data_image, get_data_plot, get_data_plot_prefs, get_dep, get_dims, get_error, get_quality, get_specresp, get_staterror, get_syserror, group, group_adapt, group_adapt_snr, group_bins, group_counts, group_snr, group_width, load_ascii, load_data, load_grouping, load_quality, set_data, set_quality, ungroup, unpack_ascii, unpack_data
filtering