SIR example: use tensorflow as default backend since jax currently fails

Author: paul-buerkner

examples/SIR_PosteriorEstimation.ipynb

@@ -23,6 +23,12 @@
     "import numpy as np\n",
     "import pandas as pd\n",
     "\n",
+    "# ensure the backend is set\n",
+    "import os\n",
+    "if \"KERAS_BACKEND\" not in os.environ:\n",
+    "    # set this to \"torch\", \"tensorflow\", or \"jax\"\n",
+    "    os.environ[\"KERAS_BACKEND\"] = \"tensorflow\"\n",
+    "\n",
     "import keras\n",
     "\n",
     "# For BayesFlow devs: this ensures that the latest dev version can be found\n",