update docs

docs/grf.rst

@@ -10,25 +10,30 @@ Gaussian angular power spectra
 
 .. autofunction:: solve
 
+.. autofunction:: compute_generic
+
+
+Transformations
+---------------
+
 .. class:: Transformation(Protocol)
 
    .. automethod:: __call__
    .. automethod:: inv
    .. automethod:: der
 
 
-Transformations
----------------
-
 .. class:: Lognormal
 
    Implements the :class:`Transformation` for lognormal fields.
 
+
 .. class:: LognormalXNormal
 
    Implements the :class:`Transformation` for the cross-correlation between
    :class:`Lognormal` and Gaussian fields.
 
+
 .. class:: SquaredNormal
 
    Implements the :class:`Transformation` for squared normal fields.

src/angst/grf.py

@@ -9,6 +9,7 @@
     "LognormalXNormal",
     "SquaredNormal",
     "Transformation",
+    "compute_generic",
     "solve",
 ]
 
@@ -218,7 +219,7 @@ def der(self, x: NDArray[Any], var: float) -> NDArray[Any]:
 Alm = NDArray[np.complexfloating[Any, Any]]
 
 
-def spectrum_from_sht(
+def compute_generic(
     cl: NDArray[Any],
     tfm: Transformation,
     sht: Callable[[NDArray[Any], int], Alm],
@@ -230,6 +231,21 @@ def spectrum_from_sht(
     transform pair *sht* and *isht* to compute a simple band-limited
     Gaussian power spectrum, without the full machinery of
     :func:`solve`.
+
+    Examples
+    --------
+    Compute a Gaussian angular power spectrum for a lognormal
+    transformation using the *healpy* spherical harmonic transform.
+
+    >>> import healpy as hp
+    >>> tfm = angst.grf.Lognormal()
+    >>> gl = angst.grf.compute_sht(
+    ...     cl,
+    ...     tfm,
+    ...     lambda m, lmax: hp.map2alm(m, lmax=lmax, use_pixel_weights=True),
+    ...     lambda alm: hp.alm2map(alm, 2048),
+    ... )
+
     """
 
     xp = cl.__array_namespace__()