calc_source_sum2d

Synopsis

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

Syntax

calc_source_sum2d(reg=None, id=None)

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

Description

This function is for two-dimensional data sets: use `calc_source_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)
>>> 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_source_sum2d()
24.0

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

>>> calc_source_sum2d('circle(22,12,1)')
8.0
>>> calc_source_sum2d('field()-circle(22,12,1)')
16.0

Example 2

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

>>> calc_source_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:

msum -- The sum of the model values that lie within the given region. This does not include any PSF included by `set_psf` .

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.