From 159f2c58eee20e437decf5e5d3e5942ce84b2b1a Mon Sep 17 00:00:00 2001
From: Lenz Fiedler <l.fiedler@hzdr.de>
Date: Thu, 12 Oct 2023 17:53:38 +0200
Subject: [PATCH] Fixed a bug when loading horovod

---
 mala/common/parameters.py | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/mala/common/parameters.py b/mala/common/parameters.py
index 314ea44ff..53b861449 100644
--- a/mala/common/parameters.py
+++ b/mala/common/parameters.py
@@ -6,8 +6,10 @@
 import pickle
 from time import sleep
 
+horovod_available = False
 try:
     import horovod.torch as hvd
+    horovod_available = True
 except ModuleNotFoundError:
     pass
 import numpy as np
@@ -1257,19 +1259,25 @@ def use_horovod(self):
 
     @use_horovod.setter
     def use_horovod(self, value):
-        if value:
-            hvd.init()
+        if value is False:
+            self._use_horovod = False
+        else:
+            if horovod_available:
+                hvd.init()
+                # Invalidate, will be updated in setter.
+                set_horovod_status(value)
+                self.device = None
+                self._use_horovod = value
+                self.network._update_horovod(self.use_horovod)
+                self.descriptors._update_horovod(self.use_horovod)
+                self.targets._update_horovod(self.use_horovod)
+                self.data._update_horovod(self.use_horovod)
+                self.running._update_horovod(self.use_horovod)
+                self.hyperparameters._update_horovod(self.use_horovod)
+            else:
+                parallel_warn("Horovod requested, but not installed found. "
+                              "MALA will operate without horovod only.")
 
-        # Invalidate, will be updated in setter.
-        set_horovod_status(value)
-        self.device = None
-        self._use_horovod = value
-        self.network._update_horovod(self.use_horovod)
-        self.descriptors._update_horovod(self.use_horovod)
-        self.targets._update_horovod(self.use_horovod)
-        self.data._update_horovod(self.use_horovod)
-        self.running._update_horovod(self.use_horovod)
-        self.hyperparameters._update_horovod(self.use_horovod)
 
     @property
     def device(self):