Reanimator Ltd

High-performance coding by Eddie Edwards


This section contains various maths-related things.

Pixel-perfect Derivatives on GPU

Quick maths hack to get the correct per-pixel derivative of any value that is linear in worldspace.

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Finding the Nth Root

This article describes how to quickly find the Nth root using basic arithmetic operations and floating-point bit-twiddling hacks.

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SVD in 2D

How to compute the SVD in 2D (includes code)

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Finding the Exact Pseudoinverse

You're going to use full-blown SVD just to get the pseudoinverse? Really?

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Matrix Decomposition for Dummies

How do all these matrix decompositions work, and how do you code them?

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When Is This Expression True?

When is this expression true for random variables A, B and C?

p(A|C) = p(A|B)p(B|C) + p(A|!B)p(!B|C)

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Quaternion Cheatsheet

Quaternion formulae for everyday use.

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