Compute Ex for PSF.
Compute scalar correlation function from
PSF ellipticity residuals to compute TEx
metrics.
Parameters
----------
de1: `np.ndarray`
PSF ellipticity residuals component 1.
de2: `np.ndarray`
PSF ellipticity residuals component 2.
ra: `np.ndarray`
Right ascension coordinate.
dec: `np.ndarray`
Declination coordinate.
units: `str`
In which units are ra and dec. units supported
are the same as the one in treecorr.
Returns
-------
struct : `lsst.pipe.base.Struct`
The struct contains the following data:
``E1``: `float`
<de1 de1> scalar correlation function, compute
in an angular bin define in TreecorrConfig.
``E2``: `float`
<de2 de2> scalar correlation function, compute
in an angular bin define in TreecorrConfig.
``Ex``: `float`
<de1 de2> scalar cross-correlation function, compute
in an angular bin define in TreecorrConfig.
Definition at line 53 of file computeExPsf.py.