Chris Lomont's Posts Page on Lomont.org

MinimalTicTacToe

Fri, 26 Jul 2024 07:50:18 -0400

Derivation of a minimal size tree for playing perfect tic tac toe

Correct alpha and gamma for image processing

Mon, 28 Aug 2023 18:40:19 -0400

This is a note on the correct usage of alpha blending, pre-multiplied alpha, gamma correction, and linear colors for image processing.

IOS PNG Errors

Sun, 23 Jul 2023 14:44:11 -0400

XCode corrupts PNG images for iOS builds. This post details the error.

Problems using SSIM for image quality comparisons

Sat, 24 Jun 2023 10:36:07 -0400

Variation among SSIM implementations make comparing results a mess. This version matches the output of the original, unlike most of those in common use as of 2023.

Accurate color conversions

Tue, 06 Jun 2023 07:12:30 -0400

This is a quick note for converting byte values colors in 0-255 back and forth to floating-point colors in 0-1 which avoids common errors.

Button debouncing and pattern matching

Tue, 22 Nov 2022 18:17:00 -0400

A robust, portable, extensible method for handling button presses when interfacing software and hardware.

A better quadratic formula algorithm

Sat, 27 Aug 2022 08:12:01 -0400

A robust algorithm for computing roots of quadratic equations, much better than common code.

Lomont floating point notes

Fri, 26 Aug 2022 08:07:00 -0400

Notes on floating point issues, including lists of facts and theorems useful for algorithm development.

Rtk Gps Project

Mon, 07 Dec 2020 20:25:57 -0500

I built a RTK-GPS gadget and wrote enough software to do basic GNS tasks such as finding distances, decoding GPS NMEA and RTCM messages, finding intersections, and doing boundary detection.

Chris Lomont's lines of code over time

Sun, 23 Jun 2019 12:10:43 -0400

Over decades I’ve written a lot of personal code. I made a bar chart race showing how many lines I’ve written in different languages over time.

New C# syntax and features

Sat, 01 Jun 2019 17:08:08 -0400

Here’s a brief summary of C# features by version.

Walking Ant Probability Problem

Wed, 01 Nov 2017 17:08:08 -0400

Here’s a math puzzle.

A Universal FRACTRAN Interpreter in FRACTRAN

Mon, 01 May 2017 17:08:08 -0400

Here’s FRACTRAN, a weird fraction based programming language, written in FRACTRAN.

Generating Uniform Random Numbers on [0,1]

Sun, 05 Mar 2017 17:08:08 -0400

How does one generate uniform random numbers in [0,1] using IEEE 754 floating point formats? It’s tricky.

Efficient divisibility testing

Tue, 21 Feb 2017 17:08:08 -0400

Here’s bit tricks for efficient divisibility testing.

Making Three NOT Gates from Two

Sat, 17 Sep 2016 17:08:08 -0400

This is a hard puzzle about using two NOT gates to build three.

Compression Notes

Mon, 29 Aug 2016 17:08:08 -0400

Here’s some notes on compression.

LZCL: An embedded compression library

Mon, 29 Aug 2016 17:08:08 -0400

Here’s an embedded compression format I designed to meet certain requirements. It’s small, fast, and efficient.

Average segment length

Tue, 23 Aug 2016 17:08:08 -0400

What’s the average length of a segment chosen uniformly by area on a unit square?

How many prisoners?

Tue, 23 Aug 2016 17:08:08 -0400

This is a nicely hard problem in the common prisoners and warden format.

Pick a Number

Tue, 23 Aug 2016 17:08:08 -0400

Here’s a result that is completely non-intuitive.

Test site features

Fri, 01 Jul 2016 17:08:08 -0400

A post to test site features such as tables, math, code…