# @stdlib/stats-incr-hmean

0.2.1 • Public • Published
About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

# incrhmean

Compute a harmonic mean incrementally.

The harmonic mean of positive real numbers `x_0, x_1, ..., x_{n-1}` is defined as

## Installation

`npm install @stdlib/stats-incr-hmean`

## Usage

`var incrhmean = require( '@stdlib/stats-incr-hmean' );`

#### incrhmean()

Returns an accumulator `function` which incrementally computes a harmonic mean.

`var accumulator = incrhmean();`

#### accumulator( [x] )

If provided an input value `x`, the accumulator function returns an updated harmonic mean. If not provided an input value `x`, the accumulator function returns the current harmonic mean.

```var accumulator = incrhmean();

var v = accumulator( 2.0 );
// returns 2.0

v = accumulator( 1.0 );
// returns ~1.33

v = accumulator( 3.0 );
// returns ~1.64

v = accumulator();
// returns ~1.64```

## Notes

• Input values are not type checked. If provided `NaN` or a value which, when used in computations, results in `NaN`, the accumulated value is `NaN` for all future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly before passing the value to the accumulator function.

## Examples

```var randu = require( '@stdlib/random-base-randu' );
var incrhmean = require( '@stdlib/stats-incr-hmean' );

var accumulator;
var v;
var i;

// Initialize an accumulator:
accumulator = incrhmean();

// For each simulated datum, update the harmonic mean...
for ( i = 0; i < 100; i++ ) {
v = randu() * 100.0;
accumulator( v );
}
console.log( accumulator() );```

## Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

See LICENSE.

## Copyright

Copyright © 2016-2024. The Stdlib Authors.

## Package Sidebar

### Install

`npm i @stdlib/stats-incr-hmean`

### Repository

github.com/stdlib-js/stats-incr-hmean

stdlib.io

49

0.2.1

Apache-2.0

43.2 kB

12