111 lines
3.2 KiB
Python
111 lines
3.2 KiB
Python
"""ProtoTorch LGMLVQ example using 2D Iris data."""
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import numpy as np
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import torch
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from matplotlib import pyplot as plt
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from sklearn.datasets import load_iris
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from sklearn.metrics import accuracy_score
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from prototorch.functions.competitions import stratified_min
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from prototorch.functions.distances import lomega_distance
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from prototorch.functions.init import eye_
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from prototorch.modules.losses import GLVQLoss
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from prototorch.modules.prototypes import Prototypes1D
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# Prepare training data
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x_train, y_train = load_iris(True)
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x_train = x_train[:, [0, 2]]
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# Define the model
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class Model(torch.nn.Module):
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def __init__(self):
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"""Local-GMLVQ model."""
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super().__init__()
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self.p1 = Prototypes1D(
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input_dim=2,
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prototype_distribution=[1, 2, 2],
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prototype_initializer="stratified_random",
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data=[x_train, y_train],
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)
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omegas = torch.zeros(5, 2, 2)
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self.omegas = torch.nn.Parameter(omegas)
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eye_(self.omegas)
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def forward(self, x):
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protos = self.p1.prototypes
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plabels = self.p1.prototype_labels
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omegas = self.omegas
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dis = lomega_distance(x, protos, omegas)
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return dis, plabels
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# Build the model
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model = Model()
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# Optimize using Adam optimizer from `torch.optim`
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optimizer = torch.optim.Adam(model.parameters(), lr=0.01)
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criterion = GLVQLoss(squashing="sigmoid_beta", beta=10)
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x_in = torch.Tensor(x_train)
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y_in = torch.Tensor(y_train)
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# Training loop
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title = "Prototype Visualization"
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fig = plt.figure(title)
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for epoch in range(100):
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# Compute loss
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dis, plabels = model(x_in)
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loss = criterion([dis, plabels], y_in)
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y_pred = np.argmin(stratified_min(dis, plabels).detach().numpy(), axis=1)
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acc = accuracy_score(y_train, y_pred)
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log_string = f"Epoch: {epoch + 1:03d} Loss: {loss.item():05.02f} "
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log_string += f"Acc: {acc * 100:05.02f}%"
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print(log_string)
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# Take a gradient descent step
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optimizer.zero_grad()
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loss.backward()
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optimizer.step()
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# Get the prototypes form the model
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protos = model.p1.prototypes.data.numpy()
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# Visualize the data and the prototypes
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ax = fig.gca()
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ax.cla()
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ax.set_title(title)
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ax.set_xlabel("Data dimension 1")
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ax.set_ylabel("Data dimension 2")
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cmap = "viridis"
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ax.scatter(x_train[:, 0], x_train[:, 1], c=y_train, edgecolor="k")
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ax.scatter(
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protos[:, 0],
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protos[:, 1],
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c=plabels,
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cmap=cmap,
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edgecolor="k",
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marker="D",
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s=50,
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)
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# Paint decision regions
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x = np.vstack((x_train, protos))
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x_min, x_max = x[:, 0].min() - 1, x[:, 0].max() + 1
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y_min, y_max = x[:, 1].min() - 1, x[:, 1].max() + 1
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xx, yy = np.meshgrid(np.arange(x_min, x_max, 1 / 50),
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np.arange(y_min, y_max, 1 / 50))
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mesh_input = np.c_[xx.ravel(), yy.ravel()]
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d, plabels = model(torch.Tensor(mesh_input))
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y_pred = np.argmin(stratified_min(d, plabels).detach().numpy(), axis=1)
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y_pred = y_pred.reshape(xx.shape)
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# Plot voronoi regions
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ax.contourf(xx, yy, y_pred, cmap=cmap, alpha=0.35)
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ax.set_xlim(left=x_min + 0, right=x_max - 0)
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ax.set_ylim(bottom=y_min + 0, top=y_max - 0)
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plt.pause(0.1)
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