calc_source_sum2d

Synopsis

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

Syntax

calc_source_sum2d(reg=None, id=None)

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	Type information	Definition
reg	str, optional	The spatial filter to use. The default, none , is to use the whole data set.
id	int, 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` .

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.