método predict
Lección 11 de 19 del curso Introducción al aprendizaje automático de Coddy.
Desafío
IntermedioEl método predict calcula la distancia de cada nuevo punto a todos los demás centroides. El punto se asigna al clúster del centroide más cercano.
Para cada punto nuevo, asigna el índice del centroide más cercano. devuelve la lista de los clústeres asignados predichos.
Pruébalo tú mismo
def euclidian_distance(point_a, point_b):
return (sum([(point_a[i] - point_b[i])**2 for i in range(len(point_a))]))**0.5
class KMeans:
def __init__(self, k):
self.k = k
def find_cluster_centroid(self, cluster_points):
# Write your code here
centroid = []
for point in cluster_points:
for dim, value in enumerate(point):
if len(centroid) - 1 < dim:
centroid.append(0)
centroid[dim] += value
for i in range(len(centroid)):
centroid[i] /= len(cluster_points)
return centroid
def fit(self, X_train):
# Write you code here
self.centroids = [X_train[i] for i in range(2, self.k*2 + 1, 2)]
while True:
# Assing each point to centroid
points_clusters = []
for point in X_train:
distances = []
for centroid in self.centroids:
dist_to_point = euclidian_distance(centroid, point)
distances.append(dist_to_point)
closest_centroid_index = distances.index(min(distances))
points_clusters.append((point, closest_centroid_index))
# Update centroids
clusters = {}
for point, cluster in points_clusters:
if cluster not in clusters:
clusters[cluster] = []
clusters[cluster].append(point)
new_centroids = [None]*self.k
for cluster, points in clusters.items():
new_centroids[cluster] = self.find_cluster_centroid(points)
# Check if converged
total_dist = 0
for i in range(len(new_centroids)):
total_dist += euclidian_distance(new_centroids[i], self.centroids[i])
if total_dist < 0.01:
break
self.centroids = new_centroids
def predict(self, X_test):
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