https://github.com/sanity/pav.rs

An implementation of the Pair Adjacent Violators algorithm for isotonic regression in Rust

https://github.com/sanity/pav.rs

Science Score: 49.0%

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Keywords

machine-learning regression rust
Last synced: 6 months ago · JSON representation

Repository

An implementation of the Pair Adjacent Violators algorithm for isotonic regression in Rust

Basic Info
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  • Stars: 10
  • Watchers: 2
  • Forks: 0
  • Open Issues: 0
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Topics
machine-learning regression rust
Created almost 5 years ago · Last pushed over 1 year ago
Metadata Files
Readme

README.md

Pair Adjacent Violators for Rust

Rust crates.io

Overview

An implementation of the Pair Adjacent Violators algorithm for isotonic regression. Note this algorithm is also known as "Pool Adjacent Violators".

What is "Isotonic Regression" and why should I care?

Imagine you have two variables, x and y, and you don't know the relationship between them, but you know that if x increases then y will increase, and if x decreases then y will decrease. Alternatively it may be the opposite, if x increases then y decreases, and if x decreases then y increases.

Examples of such isotonic or monotonic relationships include:

  • x is the pressure applied to the accelerator in a car, y is the acceleration of the car (acceleration increases as more pressure is applied)
  • x is the rate at which a web server is receiving HTTP requests, y is the CPU usage of the web server (server CPU usage will increase as the request rate increases)
  • x is the price of an item, and y is the probability that someone will buy it (this would be a decreasing relationship, as x increases y decreases)

These are all examples of an isotonic relationship between two variables, where the relationship is likely to be more complex than linear.

So we know the relationship between x and y is isotonic, and let's also say that we've been able to collect data about actual x and y values that occur in practice.

What we'd really like to be able to do is estimate, for any given x, what y will be, or alternatively for any given y, what x would be required.

But of course real-world data is noisy, and is unlikely to be strictly isotonic, so we want something that allows us to feed in this raw noisy data, figure out the actual relationship between x and y, and then use this to allow us to predict y given x, or to predict what value of x will give us a particular value of y. This is the purpose of the pair-adjacent-violators algorithm.

...and why should I care?

Using the examples I provide above:

  • A self-driving car could use it to learn how much pressure to apply to the accelerator to give a desired amount of acceleration
  • An autoscaling system could use it to help predict how many web servers they need to handle a given amount of web traffic
  • A retailer could use it to choose a price for an item that maximizes their profit (aka "yield optimization")

Isotonic regression in online advertising

If you have an hour to spare, and are interested in learning more about how online advertising works - you should check out this lecture that I gave in 2015 where I explain how we were able to use pair adjacent violators to solve some fun problems.

A picture is worth a thousand words

Here is the relationship that PAV extracts from some very noisy input data where there is an increasing relationship between x and y:

PAV in action

Features

  • Smart linear interpolation between points and extrapolation outside the training data domain
  • Fairly efficient implementation without compromizing code readability
  • Will intelligently extrapolate to compute y for values of x greater or less than those used to build the PAV model

Usage example

```rust use pav_regression::pav::{IsotonicRegression, Point};

// ..

let points = &[
    Point::new(0.0, 1.0),
    Point::new(1.0, 2.0),
    Point::new(2.0, 1.5),
];

let regression = IsotonicRegression::new_ascending(points);
assert_eq!(
    regression.interpolate(1.5), 1.75
);

```

For more examples please see the unit tests.

License

Released under the LGPL version 3 by Ian Clarke.

See also

  • An earlier implementation of PAV for Kotlin/JVM by the same author: https://github.com/sanity/pairAdjacentViolators

Owner

  • Name: Ian Clarke
  • Login: sanity
  • Kind: user
  • Location: Austin TX
  • Company: @freenet

Degree in CS & AI. Creator of freenet.org, kweb.io, 33mail.com.

GitHub Events

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Last Year
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Last synced: over 1 year ago

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  • Total Commits: 129
  • Total Committers: 4
  • Avg Commits per committer: 32.25
  • Development Distribution Score (DDS): 0.55
Past Year
  • Commits: 64
  • Committers: 2
  • Avg Commits per committer: 32.0
  • Development Distribution Score (DDS): 0.094
Top Committers
Name Email Commits
Ian Clarke g****b@i****m 58
Ian Clarke i****e@g****m 46
Ian Clarke s****y 24
Ian Clarke i****n@l****s 1
Committer Domains (Top 20 + Academic)

Issues and Pull Requests

Last synced: 6 months ago

All Time
  • Total issues: 3
  • Total pull requests: 1
  • Average time to close issues: 10 months
  • Average time to close pull requests: N/A
  • Total issue authors: 2
  • Total pull request authors: 1
  • Average comments per issue: 0.67
  • Average comments per pull request: 0.0
  • Merged pull requests: 0
  • Bot issues: 0
  • Bot pull requests: 0
Past Year
  • Issues: 0
  • Pull requests: 1
  • Average time to close issues: N/A
  • Average time to close pull requests: N/A
  • Issue authors: 0
  • Pull request authors: 1
  • Average comments per issue: 0
  • Average comments per pull request: 0.0
  • Merged pull requests: 0
  • Bot issues: 0
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Top Authors
Issue Authors
  • sanity (2)
  • Puumanamana (1)
Pull Request Authors
  • anchpop (1)
Top Labels
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bug (1)
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Packages

  • Total packages: 1
  • Total downloads:
    • cargo 35,551 total
  • Total dependent packages: 1
  • Total dependent repositories: 3
  • Total versions: 26
  • Total maintainers: 1
crates.io: pav_regression

The pair adjacent violators algorithm for isotonic regression

  • Versions: 26
  • Dependent Packages: 1
  • Dependent Repositories: 3
  • Downloads: 35,551 Total
Rankings
Dependent repos count: 11.7%
Dependent packages count: 18.2%
Downloads: 19.9%
Average: 24.4%
Stargazers count: 31.4%
Forks count: 40.7%
Maintainers (1)
Last synced: 6 months ago

Dependencies

.github/workflows/rust.yml actions
  • actions/checkout v2 composite
Cargo.toml cargo
  • rand 0.8.5 development
  • ordered-float 3.6.0
  • serde 1.0.159
  • thiserror 1.0