docs: update tutorial notebook

docs/source/tutorial.ipynb

@@ -21,7 +21,7 @@
    "id": "43b74278",
    "metadata": {},
    "source": [
-    "This is a short tutorial for the [models](https://github.com/si-cim/prototorch_models) plugin of the [ProtoTorch](https://github.com/si-cim/prototorch) framework.\n",
+    "This is a short tutorial for the [models](https://github.com/si-cim/prototorch_models) plugin of the [ProtoTorch](https://github.com/si-cim/prototorch) framework. This is by no means a comprehensive look at all the features that the framework has to offer, but it should help you get up and running.\n",
     "\n",
     "[ProtoTorch](https://github.com/si-cim/prototorch) provides [torch.nn](https://pytorch.org/docs/stable/nn.html) modules and utilities to implement prototype-based models. However, it is up to the user to put these modules together into models and handle the training of these models. Expert machine-learning practioners and researchers sometimes prefer this level of control. However, this leads to a lot of boilerplate code that is essentially same across many projects. Needless to say, this is a source of a lot of frustration. [PyTorch-Lightning](https://pytorch-lightning.readthedocs.io/en/latest/) is a framework that helps avoid a lot of this frustration by handling the boilerplate code for you so you don't have to reinvent the wheel every time you need to implement a new model.\n",
     "\n",
@@ -404,6 +404,55 @@
     "## Advanced"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "53a64063",
+   "metadata": {},
+   "source": [
+    "### Warm-start a model with prototypes learned from another model"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3177c277",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "trained_model = pt.models.GLVQ.load_from_checkpoint(\"./checkpoints/glvq_iris.ckpt\", strict=False)\n",
+    "model = pt.models.SiameseGMLVQ(\n",
+    "    dict(input_dim=2,\n",
+    "         output_dim=2,\n",
+    "         distribution=(3, 2),\n",
+    "         proto_lr=0.0001,\n",
+    "         bb_lr=0.0001),\n",
+    "    optimizer=torch.optim.Adam,\n",
+    "    prototypes_initializer=pt.initializers.LCI(trained_model.prototypes),\n",
+    "    labels_initializer=pt.initializers.LLI(trained_model.prototype_labels),\n",
+    "    omega_initializer=pt.initializers.LLTI(torch.tensor([[0., 1.], [1., 0.]])),  # permute axes\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8baee9a2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(model)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "cc203088",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "pt.models.VisSiameseGLVQ2D(data=train_ds, title=\"GMLVQ - Warm-start state\").visualize(model)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "1f6a33a5",
@@ -423,7 +472,8 @@
     "import pytorch_lightning as pl\n",
     "import torch\n",
     "from torchvision import transforms\n",
-    "from torchvision.datasets import MNIST"
+    "from torchvision.datasets import MNIST\n",
+    "from torchvision.utils import make_grid"
    ]
   },
   {
@@ -484,7 +534,7 @@
    "outputs": [],
    "source": [
     "model = pt.models.ImageGLVQ(\n",
-    "    dict(distribution=(10, 5)),\n",
+    "    dict(distribution=(10, 1)),\n",
     "    prototypes_initializer=pt.initializers.SMCI(init_ds),\n",
     ")"
    ]
@@ -496,7 +546,30 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "plt.imshow(model.get_prototype_grid(num_columns=10))"
+    "plt.imshow(model.get_prototype_grid(num_columns=5))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "1c23c7b2",
+   "metadata": {},
+   "source": [
+    "We could, of course, just use the initializers in isolation. For example, we could quickly obtain a stratified selection from the data like so:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "30780927",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "protos, plabels = pt.components.LabeledComponents(\n",
+    "    distribution=(10, 5),\n",
+    "    components_initializer=pt.initializers.SMCI(init_ds),\n",
+    "    labels_initializer=pt.initializers.LabelsInitializer(),\n",
+    ")()\n",
+    "plt.imshow(make_grid(protos, 10).permute(1, 2, 0)[:, :, 0], cmap=\"jet\")"
    ]
   },
   {
@@ -564,7 +637,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.9"
+   "version": "3.9.12"
   }
  },
  "nbformat": 4,