├── assets └── banner.png ├── tutorials ├── neural-networks-and-deep-learning │ └── neural-network │ │ └── neural_network.py └── core-machine-learning-algorithms │ ├── mean-squared-error │ └── mean_squared_error.py │ ├── mean-absolute-error │ └── mean_absolute_error.py │ ├── activation-functions │ └── activation_functions.py │ ├── linear-regression │ └── linear_regression.py │ ├── knn │ └── knn.py │ └── logistic-regression │ └── logistic_regression.py ├── LICENSE └── README.md /assets/banner.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/amitshekhariitbhu/build-your-own-x-machine-learning/HEAD/assets/banner.png -------------------------------------------------------------------------------- /tutorials/neural-networks-and-deep-learning/neural-network/neural_network.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | class NeuralNetwork: 4 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/mean-squared-error/mean_squared_error.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | def mean_squared_error(y_true, y_pred): 4 | 5 | # Calculate MSE: mean of squared differences 6 | mse = np.mean((y_true - y_pred) ** 2) 7 | return mse 8 | 9 | # Example usage 10 | if __name__ == "__main__": 11 | # Generate synthetic data 12 | np.random.seed(0) 13 | X = np.random.randn(100, 1) # 100 samples, 1 feature 14 | y_true = 3 * X.flatten() + 2 + np.random.randn(100) * 0.5 # y = 3x + 2 + noise 15 | 16 | # Simulate predictions 17 | # Assume a slightly off model: y_pred = 2.8x + 2.2 18 | y_pred = 2.8 * X.flatten() + 2.2 19 | 20 | # Calculate MSE 21 | mse = mean_squared_error(y_true, y_pred) 22 | 23 | # Print results 24 | print("Actual values (first 5):", y_true[:5]) 25 | print("Predicted values (first 5):", y_pred[:5]) 26 | print("Mean Squared Error:", mse) 27 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/mean-absolute-error/mean_absolute_error.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | def mean_absolute_error(y_true, y_pred): 4 | 5 | # Calculate MAE: mean of absolute differences 6 | mae = np.mean(np.abs(y_true - y_pred)) 7 | return mae 8 | 9 | # Example usage 10 | if __name__ == "__main__": 11 | # Generate synthetic data 12 | np.random.seed(0) 13 | X = np.random.randn(100, 1) # 100 samples, 1 feature 14 | y_true = 3 * X.flatten() + 2 + np.random.randn(100) * 0.5 # y = 3x + 2 + noise 15 | 16 | # Simulate predictions 17 | # Assume a slightly off model: y_pred = 2.8x + 2.2 18 | y_pred = 2.8 * X.flatten() + 2.2 19 | 20 | # Calculate MAE 21 | mae = mean_absolute_error(y_true, y_pred) 22 | 23 | # Print results 24 | print("Actual values (first 5):", y_true[:5]) 25 | print("Predicted values (first 5):", y_pred[:5]) 26 | print("Mean Absolute Error:", mae) 27 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/activation-functions/activation_functions.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | def sigmoid(x): 4 | return 1 / (1 + np.exp(-x)) 5 | 6 | def tanh(x): 7 | exp_x = np.exp(x) 8 | exp_neg_x = np.exp(-x) 9 | return (exp_x - exp_neg_x) / (exp_x + exp_neg_x) 10 | 11 | def relu(x): 12 | return np.maximum(0, x) 13 | 14 | def leaky_relu(x, alpha=0.01): 15 | return np.where(x > 0, x, alpha * x) 16 | 17 | def softmax(x): 18 | # Subtract max for numerical stability 19 | exp_x = np.exp(x - np.max(x, axis=-1, keepdims=True)) 20 | return exp_x / np.sum(exp_x, axis=-1, keepdims=True) 21 | 22 | # Example usage 23 | if __name__ == "__main__": 24 | # Generate synthetic input data 25 | np.random.seed(0) 26 | 27 | # For Sigmoid, Tanh, ReLU, Leaky ReLU: single array 28 | x = np.random.randn(5) # 5 scalar inputs 29 | 30 | # For Softmax: simulate scores for 3 classes 31 | x_softmax = np.random.randn(5, 3) # 5 samples, 3 classes 32 | 33 | # Calculate activations 34 | sigmoid_output = sigmoid(x) 35 | tanh_output = tanh(x) 36 | relu_output = relu(x) 37 | leaky_relu_output = leaky_relu(x, alpha=0.01) 38 | softmax_output = softmax(x_softmax) 39 | 40 | # Print results 41 | print("Input (x):", x) 42 | print("Sigmoid:", sigmoid_output) 43 | print("Tanh:", tanh_output) 44 | print("ReLU:", relu_output) 45 | print("Leaky ReLU (alpha=0.01):", leaky_relu_output) 46 | print("Softmax Input (5 samples, 3 classes):", x_softmax) 47 | print("Softmax Output:", softmax_output) 48 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/linear-regression/linear_regression.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | class LinearRegression: 4 | def __init__(self, learning_rate=0.01, n_epochs=1000): 5 | self.learning_rate = learning_rate 6 | self.n_epochs = n_epochs 7 | self.weights = None 8 | self.bias = None 9 | 10 | def fit(self, X, y): 11 | # Initialize parameters 12 | n_samples, n_features = X.shape 13 | self.weights = np.zeros(n_features) 14 | self.bias = 0 15 | 16 | # Gradient descent 17 | for _ in range(self.n_epochs): 18 | 19 | y_predicted = np.dot(X, self.weights) + self.bias 20 | 21 | # Calculate gradients 22 | dw = (1 / n_samples) * np.dot(X.T, (y_predicted - y)) 23 | db = (1 / n_samples) * np.sum(y_predicted - y) 24 | 25 | # Update parameters 26 | self.weights -= self.learning_rate * dw 27 | self.bias -= self.learning_rate * db 28 | 29 | # Calculate loss 30 | loss = np.mean((y_predicted - y) ** 2) 31 | 32 | def predict(self, X): 33 | return np.dot(X, self.weights) + self.bias 34 | 35 | # Example usage 36 | if __name__ == "__main__": 37 | # Generate sample data 38 | np.random.seed(0) 39 | X = 2 * np.random.rand(100, 1) 40 | y = 3 * X.flatten() + 4 + np.random.randn(100) 41 | 42 | # Create and train model 43 | model = LinearRegression(learning_rate=0.01, n_epochs=1000) 44 | model.fit(X, y) 45 | 46 | # Make predictions 47 | predictions = model.predict([[5], [10], [15], [20]]) 48 | 49 | # Print results 50 | print("Predictions:", predictions) 51 | print("Learned weights:", model.weights) 52 | print("Learned bias:", model.bias) 53 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/knn/knn.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | class KNN: 4 | def __init__(self, k=3): 5 | self.k = k 6 | self.X_train = None 7 | self.y_train = None 8 | 9 | def fit(self, X, y): 10 | #Store the training data. 11 | self.X_train = X 12 | self.y_train = y 13 | 14 | def predict(self, x): 15 | # Calculate Euclidean distances to all training samples 16 | distances = np.sqrt(np.sum((self.X_train - x) ** 2, axis=1)) 17 | 18 | # Get indices of k nearest neighbors 19 | k_indices = np.argsort(distances)[:self.k] 20 | 21 | # Get labels of k nearest neighbors 22 | k_nearest_labels = self.y_train[k_indices] 23 | 24 | # Return most common label (majority vote) 25 | return np.bincount(k_nearest_labels).argmax() 26 | 27 | 28 | # Example usage 29 | if __name__ == "__main__": 30 | # Generate sample data (simple linear boundaries for 3 classes) 31 | np.random.seed(0) 32 | X = np.random.rand(150, 2) * 2 # 150 samples, 2 features in [0, 2] 33 | # Assign labels based on two linear boundaries 34 | y = np.zeros(150, dtype=int) 35 | y[(X[:, 0] + X[:, 1] > 1.5)] = 1 # Class 1 if x_1 + x_2 > 1.5 36 | y[(X[:, 0] + X[:, 1] < 0.5)] = 2 # Class 2 if x_1 + x_2 < 0.5 37 | # Class 0 for 0.5 <= x_1 + x_2 <= 1.5 38 | 39 | # Create and train model 40 | model = KNN(k=3) 41 | model.fit(X, y) 42 | 43 | # Predict 44 | test_point_1 = np.array([1.5, 0.5]) # x_1 + x_2 = 2 > 1.5, should be Class 1 45 | prediction_1 = model.predict(test_point_1) 46 | test_point_2 = np.array([0.2, 0.5]) # 0.5 <= x_1 + x_2 <= 1.5, should be class 0 47 | prediction_2 = model.predict(test_point_2) 48 | 49 | # Print results 50 | print("Test point 1:", test_point_1) 51 | print("Predicted class for Test point 1:", prediction_1) 52 | print("Test point 2:", test_point_2) 53 | print("Predicted class for Test point 2:", prediction_2) 54 | -------------------------------------------------------------------------------- /tutorials/core-machine-learning-algorithms/logistic-regression/logistic_regression.py: -------------------------------------------------------------------------------- 1 | import numpy as np 2 | 3 | def sigmoid(z): 4 | # Sigmoid function to map values to (0, 1) 5 | return 1 / (1 + np.exp(-z)) 6 | 7 | class LogisticRegression: 8 | def __init__(self, learning_rate=0.01, n_epochs=1000): 9 | self.learning_rate = learning_rate 10 | self.n_epochs = n_epochs 11 | self.weights = None 12 | self.bias = None 13 | 14 | def fit(self, X, y): 15 | # Initialize parameters 16 | n_samples, n_features = X.shape 17 | self.weights = np.zeros(n_features) 18 | self.bias = 0 19 | 20 | # Gradient descent 21 | for _ in range(self.n_epochs): 22 | linear_model = np.dot(X, self.weights) + self.bias 23 | y_predicted = sigmoid(linear_model) 24 | 25 | # Calculate gradients 26 | dw = (1 / n_samples) * np.dot(X.T, (y_predicted - y)) 27 | db = (1 / n_samples) * np.sum(y_predicted - y) 28 | 29 | # Calculate parameters 30 | self.weights -= self.learning_rate * dw 31 | self.bias -= self.learning_rate * db 32 | 33 | # Calculate loss (binary cross-entropy) 34 | loss = -np.mean(y * np.log(y_predicted) + (1 - y) * np.log(1 - y_predicted )) 35 | 36 | def predict_probability(self, X): 37 | # Predict probabilities 38 | linear_model = np.dot(X, self.weights) + self.bias 39 | return sigmoid(linear_model) 40 | 41 | def predict(self, X, threshold=0.5): 42 | # Predict class labels (0 or 1) based on threshold 43 | probabilities = self.predict_probability(X) 44 | return (probabilities >= threshold).astype(int) 45 | 46 | # Example usage 47 | if __name__ == "__main__": 48 | # Generate sample data (binary classification) 49 | np.random.seed(0) 50 | X = np.random.randn(100, 2) # 100 samples, 2 features 51 | y = (X[:, 0] + X[:, 1] > 0).astype(int) # Class 1 if sum of features > 0, else 0 52 | 53 | # Create and train model 54 | model = LogisticRegression(learning_rate=0.1, n_epochs=1000) 55 | model.fit(X, y) 56 | 57 | # Make predictions 58 | predictions = model.predict([[-0.03, -1.16], [1.49, 0.43]]) 59 | 60 | # Print results 61 | print("Predictions:", predictions) 62 | print("Learned weights:", model.weights) 63 | print("Learned bias:", model.bias) 64 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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