The Machine Learning Advent Calendar Day 14: Softmax Regression in Excel

Softmax Regression extends logistic regression to handle multiple classes by computing a linear score for each class and normalizing these scores with the Softmax function to produce multiclass probabilities, all while maintaining the same loss function, gradients, and optimization process. This approach increases the number of parallel scores but preserves the core logic, enabling straightforward adaptation to multi-class classification problems. Implementing Softmax Regression in Excel enhances model transparency, allowing users to directly observe class scores, probabilities, and the evolution of coefficients over time, which facilitates better understanding and debugging of the model's behavior. This accessible implementation underscores the method's simplicity