Add knn

README.md

@@ -51,6 +51,7 @@ To assist in the development process, you may also find it useful to install
 
 ## Available models
 
+- K-Nearest Neighbors (KNN)
 - Learning Vector Quantization 1 (LVQ1)
 - Generalized Learning Vector Quantization (GLVQ)
 - Generalized Relevance Learning Vector Quantization (GRLVQ)
@@ -72,7 +73,6 @@ To assist in the development process, you may also find it useful to install
 - Robust Soft Learning Vector Quantization (RSLVQ)
 - Probabilistic Learning Vector Quantization (PLVQ)
 - Self-Incremental Learning Vector Quantization (SILVQ)
-- K-Nearest Neighbors (KNN)
 
 ## FAQ
 

examples/knn_iris.py

@@ -0,0 +1,37 @@
+"""k-NN example using the Iris dataset."""
+
+import prototorch as pt
+import pytorch_lightning as pl
+import torch
+
+if __name__ == "__main__":
+    # Dataset
+    from sklearn.datasets import load_iris
+    x_train, y_train = load_iris(return_X_y=True)
+    x_train = x_train[:, [0, 2]]
+    train_ds = pt.datasets.NumpyDataset(x_train, y_train)
+
+    # Dataloaders
+    train_loader = torch.utils.data.DataLoader(train_ds,
+                                               num_workers=0,
+                                               batch_size=150)
+
+    # Hyperparameters
+    hparams = dict(k=20)
+
+    # Initialize the model
+    model = pt.models.KNN(hparams, data=train_ds)
+
+    # Callbacks
+    vis = pt.models.VisGLVQ2D(data=(x_train, y_train))
+
+    # Setup trainer
+    trainer = pl.Trainer(max_epochs=1, callbacks=[vis])
+
+    # Training loop
+    # This is only for visualization. k-NN has no training phase.
+    trainer.fit(model, train_loader)
+
+    # Recall
+    y_pred = model.predict(torch.tensor(x_train))
+    print(y_pred)

examples/siamese_glvq_iris.py

@@ -24,9 +24,7 @@ class Backbone(torch.nn.Module):
 
 if __name__ == "__main__":
     # Dataset
-    from sklearn.datasets import load_iris
+    train_ds = pt.datasets.Iris()
-    x_train, y_train = load_iris(return_X_y=True)
-    train_ds = pt.datasets.NumpyDataset(x_train, y_train)
 
     # Reproducibility
     pl.utilities.seed.seed_everything(seed=2)
@@ -39,7 +37,7 @@ if __name__ == "__main__":
     # Hyperparameters
     hparams = dict(
         distribution=[1, 2, 3],
-        prototype_initializer=pt.components.SMI((x_train, y_train)),
+        prototype_initializer=pt.components.SMI(train_ds),
         proto_lr=0.01,
         bb_lr=0.01,
     )
@@ -54,7 +52,7 @@ if __name__ == "__main__":
     print(model)
 
     # Callbacks
-    vis = pt.models.VisSiameseGLVQ2D(data=(x_train, y_train), border=0.1)
+    vis = pt.models.VisSiameseGLVQ2D(data=train_ds, border=0.1)
 
     # Setup trainer
     trainer = pl.Trainer(max_epochs=100, callbacks=[vis])

prototorch/models/__init__.py

@@ -1,7 +1,9 @@
 from importlib.metadata import PackageNotFoundError, version
 
 from .cbc import CBC
-from .glvq import GLVQ, GMLVQ, GRLVQ, LVQMLN, ImageGLVQ, SiameseGLVQ, LVQ1, LVQ21
+from .glvq import (GLVQ, GMLVQ, GRLVQ, LVQ1, LVQ21, LVQMLN, ImageGLVQ,
+                   SiameseGLVQ)
+from .knn import KNN
 from .neural_gas import NeuralGas
 from .vis import *
 

prototorch/models/knn.py

@@ -0,0 +1,62 @@
+"""The popular K-Nearest-Neighbors classification algorithm."""
+
+import warnings
+
+import torch
+import torchmetrics
+from prototorch.components import LabeledComponents
+from prototorch.components.initializers import parse_init_arg
+from prototorch.functions.competitions import knnc
+from prototorch.functions.distances import euclidean_distance
+
+from .abstract import AbstractPrototypeModel
+
+
+class KNN(AbstractPrototypeModel):
+    """K-Nearest-Neighbors classification algorithm."""
+    def __init__(self, hparams, **kwargs):
+        super().__init__()
+
+        self.save_hyperparameters(hparams)
+
+        # Default Values
+        self.hparams.setdefault("k", 1)
+        self.hparams.setdefault("distance", euclidean_distance)
+
+        data = kwargs.get("data")
+        x_train, y_train = parse_init_arg(data)
+
+        self.proto_layer = LabeledComponents(initialized_components=(x_train,
+                                                                     y_train))
+
+        self.train_acc = torchmetrics.Accuracy()
+
+    @property
+    def prototype_labels(self):
+        return self.proto_layer.component_labels.detach().cpu()
+
+    def forward(self, x):
+        protos, _ = self.proto_layer()
+        dis = self.hparams.distance(x, protos)
+        return dis
+
+    def predict(self, x):
+        # model.eval()  # ?!
+        with torch.no_grad():
+            d = self(x)
+            plabels = self.proto_layer.component_labels
+            y_pred = knnc(d, plabels, k=self.hparams.k)
+        return y_pred.numpy()
+
+    def training_step(self, train_batch, batch_idx, optimizer_idx=None):
+        return 1
+
+    def on_train_batch_start(self,
+                             train_batch,
+                             batch_idx,
+                             dataloader_idx=None):
+        warnings.warn("k-NN has no training, skipping!")
+        return -1
+
+    def configure_optimizers(self):
+        return None

setup.py

@@ -19,7 +19,7 @@ DOWNLOAD_URL = "https://github.com/si-cim/prototorch_models.git"
 with open("README.md", "r") as fh:
     long_description = fh.read()
 
-INSTALL_REQUIRES = ["prototorch>=0.4.2", "pytorch_lightning", "torchmetrics"]
+INSTALL_REQUIRES = ["prototorch>=0.4.4", "pytorch_lightning", "torchmetrics"]
 DEV = ["bumpversion"]
 EXAMPLES = ["matplotlib", "scikit-learn"]
 TESTS = ["codecov", "pytest"]