null: document integrate_times parameter of null_geodesics()

1 files changed, 5 insertions, 2 deletions

diff --git a/null.py b/null.py
index 2ba59f0..f1328b9 100644
--- a/null.py
+++ b/null.py
@@ -170,8 +170,8 @@ def null_geodesics(times, X, gXX, gtt,
     """
     Compute null geodesics along a axis, assuming zero shift.
 
-    For every coordinate time times[i], integrate a null geodesic from
-    (t=times[i], x=0) forward and backward in time.
+    For every coordinate time integrate_times[i], integrate a null geodesic from
+    (t=integrate_times[i], x=0) forward and backward in time.
 
     :param array_like times: 1D array of coordinate times at which gXX and gtt
                              are provided, must be uniform
@@ -192,6 +192,9 @@ def null_geodesics(times, X, gXX, gtt,
                               Defaults to 1.0 for each geodesic if not supplied.
     :param int interp_order: order of the Lagrange interpolation used for gXX
                              and gtt.
+    :param array_like integrate_times: 1D array of coordinate times from which
+        each geodesic will be integrated; or to put it differntly, of coordinate
+        times at which each geodesic hits X=0.
 
     :return: A len(times)-sized list of scipy.integrate.OdeSolution, each
              describing the null geodesic shot from the corresponding coordinate