# The P² algorithm for dynamic calculation of quantiles and histograms without storing observations

The P² quantile estimator is a fast sequential estimator that uses $O(1)$ memory. Allows implementing lightweight real-time monitoring of various indicators in software systems.

## Abstract

What constitutes a dangerous equation? There are two obvious interpretations: Some equations are dangerous if you know them, and others are dangerous if you do not.

## Reference

Raj Jain, Imrich Chlamtac

“The P² algorithm for dynamic calculation of quantiles and histograms without storing observations”(1985) DOI: 10.1145/4372.4378

```
@Article{jain1985,
title = {The P² algorithm for dynamic calculation of quantiles and histograms without storing observations},
abstract = {What constitutes a dangerous equation? There are two obvious interpretations: Some equations are dangerous if you know them, and others are dangerous if you do not.},
volume = {28},
issn = {1557-7317},
url = {http://dx.doi.org/10.1145/4372.4378},
doi = {10.1145/4372.4378},
number = {10},
journal = {Communications of the ACM},
publisher = {Association for Computing Machinery (ACM)},
author = {Jain, Raj and Chlamtac, Imrich},
year = {1985},
month = {oct},
pages = {1076–1085}
}
```