added ridge regression

Author: ankana2113

machine_learning/ridge_regression/model.py

@@ -1,112 +1,57 @@
 import numpy as np
-
-"""# Ridge Regression Class
-class RidgeRegression:
-    def __init__(self, learning_rate=0.01, num_iterations=1000, regularization_param=0.1):
-        self.learning_rate = learning_rate
-        self.num_iterations = num_iterations
-        self.regularization_param = regularization_param
-        self.weights = None
-        self.bias = None
-
-    def fit(self, X, y):
-        n_samples, n_features = X.shape
-        
-        # initializing weights and bias
-        self.weights = np.zeros(n_features)
-        self.bias = 0
-        
-        # gradient descent
-        for _ in range(self.num_iterations):
-            y_predicted = np.dot(X, self.weights) + self.bias
-            
-            # gradients for weights and bias
-            dw = (1/n_samples) * np.dot(X.T, (y_predicted - y)) + (self.regularization_param / n_samples) * self.weights
-            db = (1/n_samples) * np.sum(y_predicted - y)
-            
-            # updating weights and bias
-            self.weights -= self.learning_rate * dw
-            self.bias -= self.learning_rate * db
-
-    def predict(self, X):
-        return np.dot(X, self.weights) + self.bias
-
-    def mean_absolute_error(self, y_true, y_pred):
-        return np.mean(np.abs(y_true - y_pred))
-
-# Load Data Function
-def load_data(file_path):
-    data = []
-    with open(file_path, 'r') as file:
-        for line in file.readlines()[1:]:  
-            features = line.strip().split(',')
-            data.append([float(f) for f in features])
-    return np.array(data)
-
-# Example usage
-if __name__ == "__main__":
-    
-    data = load_data('ADRvsRating.csv')
-    X = data[:, 0].reshape(-1, 1)  # independent features
-    y = data[:, 1]  # dependent variable
-    
-    # initializing and training Ridge Regression model
-    model = RidgeRegression(learning_rate=0.001, num_iterations=1000, regularization_param=0.1)
-    model.fit(X, y)
-    
-    # predictions
-    predictions = model.predict(X)
-    
-    # mean absolute error
-    mae = model.mean_absolute_error(y, predictions)
-    print(f"Mean Absolute Error: {mae}")
-    
-    # final output weights and bias
-    print(f"Optimized Weights: {model.weights}")
-    print(f"Bias: {model.bias}")"""
-
 import pandas as pd
+
 class RidgeRegression:
-    def __init__(self, alpha=0.001, lambda_=0.1, iterations=1000):
+    def __init__(self, alpha=0.001, regularization_param=0.1, num_iterations=1000):
         self.alpha = alpha
-        self.lambda_ = lambda_
-        self.iterations = iterations
+        self.regularization_param = regularization_param
+        self.num_iterations = num_iterations
         self.theta = None
 
+
     def feature_scaling(self, X):
         mean = np.mean(X, axis=0)
         std = np.std(X, axis=0)
+        
         # avoid division by zero for constant features (std = 0)
         std[std == 0] = 1  # set std=1 for constant features to avoid NaN
+        
         X_scaled = (X - mean) / std
         return X_scaled, mean, std
 
+
     def fit(self, X, y):
         X_scaled, mean, std = self.feature_scaling(X)
         m, n = X_scaled.shape
         self.theta = np.zeros(n)  # initializing weights to zeros
-        for i in range(self.iterations):
+        
+        for i in range(self.num_iterations):
             predictions = X_scaled.dot(self.theta)
             error = predictions - y
+            
             # computing gradient with L2 regularization
-            gradient = (X_scaled.T.dot(error) + self.lambda_ * self.theta) / m
+            gradient = (X_scaled.T.dot(error) + self.regularization_param * self.theta) / m
             self.theta -= self.alpha * gradient  # updating weights
 
+
     def predict(self, X):
         X_scaled, _, _ = self.feature_scaling(X)
         return X_scaled.dot(self.theta)
 
+
     def compute_cost(self, X, y):
         X_scaled, _, _ = self.feature_scaling(X)  
         m = len(y)
+        
         predictions = X_scaled.dot(self.theta)
-        cost = (1 / (2 * m)) * np.sum((predictions - y) ** 2) + (
-            self.lambda_ / (2 * m)
-        ) * np.sum(self.theta**2)
+        cost = (1 / (2 * m)) * np.sum((predictions - y) ** 2) + (self.regularization_param / (2 * m)) * np.sum(self.theta**2)
         return cost
 
+
     def mean_absolute_error(self, y_true, y_pred):
         return np.mean(np.abs(y_true - y_pred))
+    
+
 # Example usage
 if __name__ == "__main__":
     df = pd.read_csv("ADRvsRating.csv")
@@ -118,7 +63,7 @@ def mean_absolute_error(self, y_true, y_pred):
     X = np.c_[np.ones(X.shape[0]), X] 
 
     # initialize and train the Ridge Regression model
-    model = RidgeRegression(alpha=0.01, lambda_=0.1, iterations=1000)
+    model = RidgeRegression(alpha=0.01, regularization_param=0.1, num_iterations=1000)
     model.fit(X, y)
 
     # predictions