Colab tutorials (#367)

* Colab Button & Run added

tutorials/tutorial4/tutorial.ipynb

@@ -5,7 +5,9 @@
    "id": "48dd2795",
    "metadata": {},
    "source": [
-    "# Tutorial: Unstructured convolutional autoencoder via continuous convolution"
+    "# Tutorial: Unstructured convolutional autoencoder via continuous convolution\n",
+    "\n",
+    "[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/mathLab/PINA/blob/master/tutorials/tutorial4/tutorial.ipynb)"
    ]
   },
   {
@@ -26,11 +28,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "id": "5ae7c0e8",
    "metadata": {},
    "outputs": [],
    "source": [
+    "## routine needed to run the notebook on Google Colab\n",
+    "try:\n",
+    "  import google.colab\n",
+    "  IN_COLAB = True\n",
+    "except:\n",
+    "  IN_COLAB = False\n",
+    "if IN_COLAB:\n",
+    "  !pip install \"pina-mathlab\"\n",
+    "\n",
     "import torch \n",
     "import matplotlib.pyplot as plt \n",
     "from pina.problem import AbstractProblem\n",
@@ -1093,7 +1104,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.7"
+   "version": "3.10.13"
   }
  },
  "nbformat": 4,