From 77d6c609d5f7cbd3e0151dce37076ca2e9247595 Mon Sep 17 00:00:00 2001
From: Ricardo <ricardo.vieira1994@gmail.com>
Date: Fri, 14 May 2021 11:33:07 +0200
Subject: [PATCH] Fix _check_start_shape

---
 pymc3/sampling.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pymc3/sampling.py b/pymc3/sampling.py
index 3a70cc38dbe..434ee232e06 100644
--- a/pymc3/sampling.py
+++ b/pymc3/sampling.py
@@ -684,6 +684,11 @@ def sample(
 def _check_start_shape(model, start):
     if not isinstance(start, dict):
         raise TypeError("start argument must be a dict or an array-like of dicts")
+
+    # Filter "non-input" variables
+    initial_point = model.initial_point
+    start = {k: v for k, v in deepcopy(start).items() if k in initial_point}
+
     e = ""
     for var in model.basic_RVs:
         var_shape = model.fastfn(var.shape)(start)