# least squares — RSS Amplifier Recent posts from the 5 feeds in the RSS Amplifier directory that cover least squares. Page: Feed: --- ## [Powell’s Dogleg for Least Squares Minimization from Scratch](https://geo-ant.github.io/blog/2026/powells-dogleg-least-squares-from-scratch/) _2026-06-17 · Geo’s Notepad_ I’ve recently released the Rust dogleg crate and I thought I’d document everything that’s needed to implement a least-squares Dogleg optimizer from scratch. You probably don’t want to do that, but if you did, then here’s everything you need to know. ## [A Simple Image Brightness And Contrast Adjustment Technique](https://geo-ant.github.io/blog/2026/simple-image-contrast-brightness-adjustment/) _2026-05-18 · Geo’s Notepad_ I recently found myself squinting at two images at work and wondering if one is actually “better” than the other. The two images were showing the same object, but they had slightly but noticeably different value ranges. That made it hard for me to understand which of the differences were due to display brightness and contrast settings and which were part of the actual structure of the image. Then… ## [A Skateboard Isn’t a Vertical Slice of a Car But It Should Be](https://geo-ant.github.io/blog/2026/making-sense-of-mvp/) _2026-04-07 · Geo’s Notepad_ It’s been one too many times that I’ve seen the famous skateboard, scooter, bike, motorcycle, and car image by Henrik Kniberg, which he says is about (agile) “product development in general”. I’ve finally figured out what bothers me about it so much. I’ll argue that the underlying mental model is at best not helpful and at worst actively misleading for product development, despite the article… ## [BCES 2.0: Now with weighted least squares](https://residuals.bearblog.dev/bces-20-now-with-weighted-least-squares/) _2026-03-20 · residuals · Residuals_ I just released a major new version of BCES , the Python package for linear regression with measurement errors. In version 2.0, the big addition is weighted least squares (WLS) regression. What's new BCES has handled the case where both X and Y have measurement errors since version 1.0, using the bivariate correlated errors and intrinsic scatter method from Akritas & Bershady (1996) . But there's… ## [You are probably overpaying for intelligence](https://residuals.bearblog.dev/you-are-probably-overpaying-for-intelligence/) _2026-02-13 · residuals · Residuals_ Abstract The leading AI models keep getting more expensive, but are they worth it? I benchmarked dozens of LLMs across coding and general reasoning tasks, then mapped their performance against API pricing. The results are striking: a handful of models—most notably DeepSeek V3.2 and Minimax 2.5—deliver 85–95% of frontier performance at a fraction of the cost. Meanwhile, premium models like Claude… ## [pip-select, an interactive tool for updating pip-installed python packages (conda-friendly)](https://residuals.bearblog.dev/pip-select-an-interactive-tool-for-updating-pip-installed-python-packages-conda-friendly/) _2026-02-01 · residuals · Residuals_ I was tired of manually figuring out which of my pip-installed packages need to be updated while excluding the conda ones, so I just created a tool that takes care of this. You fire pip-select , and it will check which of your pip packages can be updated while excluding the ones managed by conda, with a nice progress bar: Conda environment detected at: /home/user/miniconda3/envs/myenv Detected 84… ## [The state of agentic coding](https://residuals.bearblog.dev/the-state-of-agentic-coding/) _2026-01-25 · residuals · Residuals_ With the explosion of Claude Code , developers are struggling with handle the credit limits. I have seen plenty of Reddit posts complaining about the limitations imposed by the Claude Max plan, even though it costs a whopping $200! I access Anthropic’s models using the Poe API service , which also gives me access to models by the other major players in the field. In my experience with CC so far, I… ## [From horizon scales to cocoons: My favorite black hole papers of 2025](https://residuals.bearblog.dev/from-horizon-scales-to-cocoons-my-favorite-black-hole-papers-of-2025/) _2026-01-08 · residuals · Residuals_ New year, new science. Time to think about my favorite papers of 2025. This is of course a hugely biased list, convolved with my personal scientific preferences. This list will be focused on the topics of black hole astrophysics. Phenomenology: AGNs, little red dots Not a terribly exciting year on the observational front for AGNs and black hole binaries. If you discount little red dots, that is.… ## [Sample Size Calculations for Binomial Distributions](https://geo-ant.github.io/blog/2025/binomial-sample-size-calculations/) _2025-11-18 · Geo’s Notepad_ Say we have a sequence of independent Bernoulli experiments and we want to make claims about the true probability of success, given our observations. How many trials do we need to make claims about the true probability with a certain confidence? Let’s derive this from first principles. ## [The Method of Least Squares for Software Developers](https://tulon.github.io/the-method-of-least-squares-for-software-developers/) _2025-08-04 · Joseph Artsimovich · Complex Problems, Elegant Solutions_ Introduction The Method of Least Squares Show Me The Code! Deriving the Normal Equation Finding the Closest Points on Two Lines Closing Words Introduction I am a seasoned C++ developer and in many of my jobs I also interviewed job candidates. I normally interview for C++ but when the role involves graphics, I also interview for Linear Algebra. One of the Linear Algebra problems I give to… ## [Stop CI/CD & Supply-Chain Attacks (Sponsored)](https://crawlproof.com/a/IjgOrvcNo2Rp) _2025-08-03 · **Sponsored**_ Per-PR: 17 CI/CD checks and package malware scans with inline Check Run findings. ## [A Tale of Testability and Sending Non-Send Types in Rust](https://geo-ant.github.io/blog/2025/rust-testability-and-non-send-types/) _2025-05-24 · Geo’s Notepad_ This is a story of testability, multithreading, and the age old question of how do we send a !Send type in Rust. I’ll explore how (not) to do this, while rambling on about how writing obsessively testable code leads to better design. Hot takes incoming. ## [How to Implement Spline Fitting](https://tulon.github.io/spline-fitting/) _2025-03-23 · Joseph Artsimovich · Complex Problems, Elegant Solutions_ Introduction Splines Spline Fitting - First Steps The Optimization Problem Optimizing It Show Me the Code! Challenges and Improvements Avoiding Loops Adding Constraints Lagrange Multipliers Closing Words Introduction In this article, I’ll show you how I implemented spline fitting in Scan Tailor, which is a tool for post-processing scanned or photographed pages. I am the original author of that… ## [Solving Variable Projection with QR Decomposition](https://geo-ant.github.io/blog/2025/qr-based-varpro/) _2025-03-16 · Geo’s Notepad_ This article continues the series on Variable Projection and explains how to rewrite the problem using QR decomposition, rather than the more computationally expensive singular value decomposition (SVD). ## [Cursed Linear Types In Rust](https://geo-ant.github.io/blog/2024/rust-linear-types-use-once/) _2024-11-27 · Geo’s Notepad_ Inspired by Jack Wrenn’s post on Undroppable Types in Rust, I set out to see if it’s possible to create types that must be used exactly once. From my understanding, those things are called linear types, but don’t quote me on that1. Unless you are quoting the title of this article which explicitly says linear types… I feel stupid now. ## [Rethinking Builders… with Lazy Generics](https://geo-ant.github.io/blog/2024/rust-rethinking-builders-lazy-generics/) _2024-10-11 · Geo’s Notepad_ While using compile-time builder generator crates, I realized that I had run into a niche problem that required lot more flexibility with generic structs and functions than I was getting. If you like, follow me down a rabbit hole and explore the builder pattern from a very generic-centric perspective. ## [The Covariance Matrix for Variable Projection with Multiple Right Hand Sides](https://geo-ant.github.io/blog/2024/covariance-varpro-mrhs/) _2024-09-30 · Geo’s Notepad_ In this article, I explore how to efficiently calculate the covariance matrix of the best fit parameters for global fitting problems that use the variable projection (VarPro) algorithm. It’s a very niche topic, but I do need it for my open source library so I might as well write it down. It might be helpful for people looking to gain a deeper understanding of the math behind VarPro.