save decision tree

Phase 3/utils.py

@@ -6,6 +6,8 @@ import cv2
 import numpy as np
 from scipy.stats import pearsonr
 
+from collections import defaultdict
+
 # from scipy.sparse.linalg import svds
 # from sklearn.decomposition import NMF
 from sklearn.decomposition import LatentDirichletAllocation
@@ -20,6 +22,8 @@ from torchvision.models import resnet50, ResNet50_Weights
 
 import tensorly as tl
 
+import heapq
+
 # OS and env
 import json
 import os
@@ -66,3 +70,155 @@ valid_feature_models = {
     "fc": "fc_fd",
     "resnet": "resnet_fd",
 }
+
+class Node:
+    def __init__(self, feature=None, threshold=None, left=None, right=None, value=None):
+        self.feature = feature
+        self.threshold = threshold
+        self.left = left
+        self.right = right
+        self.value = value
+
+class DecisionTree:
+    def __init__(self, max_depth=None):
+        self.max_depth = max_depth
+        self.tree = None
+    
+    def entropy(self, y):
+        _, counts = np.unique(y, return_counts=True)
+        probabilities = counts / len(y)
+        return -np.sum(probabilities * np.log2(probabilities))
+    
+    def information_gain(self, X, y, feature, threshold):
+        left_idxs = X[:, feature] <= threshold
+        right_idxs = ~left_idxs
+        
+        left_y = y[left_idxs]
+        right_y = y[right_idxs]
+        
+        p_left = len(left_y) / len(y)
+        p_right = len(right_y) / len(y)
+        
+        gain = self.entropy(y) - (p_left * self.entropy(left_y) + p_right * self.entropy(right_y))
+        return gain
+    
+    def find_best_split(self, X, y):
+        best_gain = 0
+        best_feature = None
+        best_threshold = None
+        
+        for feature in range(X.shape[1]):
+            thresholds = np.unique(X[:, feature])
+            for threshold in thresholds:
+                gain = self.information_gain(X, y, feature, threshold)
+                if gain > best_gain:
+                    best_gain = gain
+                    best_feature = feature
+                    best_threshold = threshold
+        
+        return best_feature, best_threshold
+    
+    def build_tree(self, X, y, depth=0):
+        if len(np.unique(y)) == 1 or depth == self.max_depth:
+            return Node(value=np.argmax(np.bincount(y)))
+        
+        best_feature, best_threshold = self.find_best_split(X, y)
+        
+        if best_feature is None:
+            return Node(value=np.argmax(np.bincount(y)))
+        
+        left_idxs = X[:, best_feature] <= best_threshold
+        right_idxs = ~left_idxs
+        
+        left_subtree = self.build_tree(X[left_idxs], y[left_idxs], depth + 1)
+        right_subtree = self.build_tree(X[right_idxs], y[right_idxs], depth + 1)
+        
+        return Node(feature=best_feature, threshold=best_threshold, left=left_subtree, right=right_subtree)
+    
+    def fit(self, X, y):
+        X = np.array(X)  # Convert to NumPy array
+        y = np.array(y)  # Convert to NumPy array
+        self.tree = self.build_tree(X, y)
+    
+    def predict_instance(self, x, node):
+        if node.value is not None:
+            return node.value
+        
+        if x[node.feature] <= node.threshold:
+            return self.predict_instance(x, node.left)
+        else:
+            return self.predict_instance(x, node.right)
+    
+    def predict(self, X):
+        X = np.array(X)  # Convert to NumPy array
+        predictions = []
+        for x in X:
+            pred = self.predict_instance(x, self.tree)
+            predictions.append(pred)
+        return np.array(predictions)
+
+class LSHIndex:
+    def __init__(self, num_layers, num_hashes, dimensions, seed=42):
+        self.num_layers = num_layers
+        self.num_hashes = num_hashes
+        self.dimensions = dimensions
+        self.index = [defaultdict(list) for _ in range(num_layers)]
+        self.hash_functions = self._generate_hash_functions(seed)
+
+    def _generate_hash_functions(self, seed):
+        np.random.seed(seed)
+        hash_functions = []
+        for _ in range(self.num_layers):
+            layer_hashes = []
+            for _ in range(self.num_hashes):
+                random_projection = np.random.randn(self.dimensions)
+                random_projection /= np.linalg.norm(random_projection)
+                layer_hashes.append(random_projection)
+            hash_functions.append(layer_hashes)
+        return hash_functions
+
+    def hash_vector(self, vector):
+        hashed_values = []
+        for i in range(self.num_layers):
+            layer_hashes = self.hash_functions[i]
+            layer_hash = [int(np.dot(vector, h) > 0) for h in layer_hashes]
+            hashed_values.append(tuple(layer_hash))
+        return hashed_values
+
+    def add_vector(self, vector, image_id):
+        hashed = self.hash_vector(vector)
+        for i in range(self.num_layers):
+            self.index[i][hashed[i]].append((image_id, vector))
+
+    def query(self, query_vector):
+        hashed_query = self.hash_vector(query_vector)
+        candidates = set()
+        for i in range(self.num_layers):
+            candidates.update(self.index[i][hashed_query[i]])
+        return candidates
+
+    def query_t_unique(self, query_vector, t):
+        hashed_query = self.hash_vector(query_vector)
+        candidates = []
+        unique_vectors = set()  # Track unique vectors considered
+
+        for i in range(self.num_layers):
+            candidates.extend(self.index[i][hashed_query[i]])
+
+        # Calculate Euclidean distance between query and candidate vectors
+        distances = []
+        for candidate in candidates:
+            unique_vectors.add(tuple(candidate[1]))  # Adding vectors to track uniqueness
+            # unique_vectors.add((candidate))  # Adding vectors to track uniqueness
+            distance = np.linalg.norm(candidate[0] - query_vector)
+            distances.append(distance)
+
+        # Sort candidates based on Euclidean distance and get t unique similar vectors
+        unique_similar_vectors = []
+        for distance, candidate in sorted(zip(distances, candidates)):
+            if len(unique_similar_vectors) >= t:
+                break
+            if tuple(candidate) not in unique_similar_vectors:
+                unique_similar_vectors.append(tuple(candidate))
+
+        return list(unique_similar_vectors), len(unique_vectors), len(candidates)