From c0e3c433d02c80fe851a265b6f4dab2c2623ae95 Mon Sep 17 00:00:00 2001
From: Fabian Joswig <fabian.joswig@ed.ac.uk>
Date: Wed, 16 Nov 2022 10:43:12 +0000
Subject: [PATCH] docs: warning added to docstring of covariance.

---
 pyerrors/obs.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pyerrors/obs.py b/pyerrors/obs.py
index fb195644..02d16103 100644
--- a/pyerrors/obs.py
+++ b/pyerrors/obs.py
@@ -1430,6 +1430,9 @@ def correlate(obs_a, obs_b):
 def covariance(obs, visualize=False, correlation=False, smooth=None, **kwargs):
     r'''Calculates the error covariance matrix of a set of observables.
 
+    WARNING: This function should be used with care, especially for observables with support on multiple
+             ensembles with differing autocorrelations. See the notes below for details.
+
     The gamma method has to be applied first to all observables.
 
     Parameters