fix backcast creation in N_BEATS model

Author: mrdbourke

Diff for: 10_time_series_forecasting_in_tensorflow.ipynb

@@ -7,7 +7,7 @@
       "name": "10_time_series_forecasting_in_tensorflow.ipynb",
       "provenance": [],
       "collapsed_sections": [],
-      "authorship_tag": "ABX9TyOg0AjtO/b6HxZxVx292gML",
+      "authorship_tag": "ABX9TyOn99CSV9y2h4ZBT3mbjba3",
       "include_colab_link": true
     },
     "kernelspec": {
@@ -6706,7 +6706,7 @@
         "stack_input = layers.Input(shape=(INPUT_SIZE), name=\"stack_input\")\n",
         "\n",
         "# 3. Create initial backcast and forecast input (backwards predictions are referred to as residuals in the paper)\n",
-        "residuals, forecast = nbeats_block_layer(stack_input)\n",
+        "backcast, forecast = nbeats_block_layer(stack_input)\n",
         "# Add in subtraction residual link, thank you to: https://github.com/mrdbourke/tensorflow-deep-learning/discussions/174 \n",
         "residuals = layers.subtract([stack_input, backcast], name=f\"subtract_00\") \n",
         "\n",