Author Archives: jamesdmccaffrey

AdaBoost.R2 Regression with Extra Trees (Extremely Randomized Trees) Learners Using C#

Bottom line: I decided to implement AdaBoost.R2 regression using Extra (“Extremely Randomized”) Trees learners. Bottom line: For my demo dataset, the technique worked better than the standard architecture that uses regular decision trees as the learners. As is often the … Continue reading →

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NFL 2026 Season – A Look Back at How Vegas Favorites and Underdogs Did in 2025

Zoltar is my NFL football prediction system. It uses a neural network and a type of reinforcement learning. The 2026 season will be starting soon (Wednesday, Sept. 9, 2026). I figured I’d take a look at the 2025 season results, … Continue reading →

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Deep Neural Network Regression From Scratch Using Python

One Sunday evening, I was sitting in my living room. I decided to implement a regression system (to predict a single numeric value), using a neural network with exactly two hidden layers, from scratch, using Python with NumPy. The effort … Continue reading →

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Hybrid Quadratic Regression and Nearest Neighbors Regression Using C#

I like to write code every day. Writing code is a skill that must be practiced, and I enjoy writing code. Over the course of my career, I saw countless colleagues move from an engineering role to an engineering-management role, … Continue reading →

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New Version of Quadratic Regression Trained Using MP Pseudo-Inverse via QR-Householder Using C#

The goal of a machine learning regression problem is to predict a single numeric value. Quadratic regression is an enhanced form of basic linear regression. One of several ways to train a quadratic regression model is to use relaxed Moore-Penrose … Continue reading →

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Demonstrating Why AdaBoost.R2 Regression Almost Always Uses Decision Tree Learners

AdaBoost.R2 (“adaptive boosting regression, version 2”) is a technique to predict a single numeric value. AdaBoost works by creating a collection of simple decision trees. The final prediction is the average of all the tree predictions. Each tree is trained … Continue reading →

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NFL 2026 Season – A Look at Back at 2025 Vegas Point Spread Data

Zoltar is my computer program that predicts the results of NFL football games. The 2026 season will be starting soon. One morning before work, I figured I’d look at the Las Vegas point spreads for last season (2025). Starting in … Continue reading →

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Linear Regression With SGD Training and Consecutive Euclidean Distance Early Exit From Scratch Using C#

In general, when training a machine learning regression model using stochastic gradient descent, I do not use early-exit from the training loop. Any type of early-exit requires some sort of parameter that must be determined by trial and error, which … Continue reading →

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Quadratic Regression with Direct QR-Householder OLS Solve Training Using C#

Machine learning quadratic regression is a technique to predict a single numeric value. There are many ways to train a quadratic regression model. One training approach that is fast, reliable, and scales to large datasets — but is very complicated … Continue reading →

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My Top Ten Favorite Giant Insect Movies of the 1950s

I am a big fan of early science fiction movies of the 1950s. Quite a few of these movies feature giant insects (where I relax my definition of insect to allow spiders and scorpions). Here are my top 10 favorites. … Continue reading →

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