@stdlib/stats-incr-nansum

Compute a sum incrementally, ignoring NaN values.


Keywords
stdlib, stdmath, statistics, stats, mathematics, math, summation, sum, total, incremental, accumulator, javascript, node, node-js, nodejs
License
Apache-2.0
Install
npm install @stdlib/stats-incr-nansum@0.0.5

Documentation

incrnansum

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Compute a sum incrementally, ignoring NaN values.

The sum is defined as

Equation for the sum.

Installation

npm install @stdlib/stats-incr-nansum

Usage

var incrnansum = require( '@stdlib/stats-incr-nansum' );

incrnansum()

Returns an accumulator function which incrementally computes a sum, ignoring NaN values.

var accumulator = incrnansum();

accumulator( [x] )

If provided an input value x, the accumulator function returns an updated sum. If not provided an input value x, the accumulator function returns the current sum.

var accumulator = incrnansum();

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

sum = accumulator( 1.0 );
// returns 3.0

sum = accumulator( NaN );
// returns 3.0

sum = accumulator( 3.0 );
// returns 6.0

sum = accumulator();
// returns 6.0

Notes

  • Input values are not type checked. If non-numeric inputs are possible, you are advised to type check and handle accordingly before passing the value to the accumulator function.
  • For long running accumulations or accumulations of large numbers, care should be taken to prevent overflow.

Examples

var randu = require( '@stdlib/random-base-randu' );
var incrnansum = require( '@stdlib/stats-incr-nansum' );

var accumulator;
var v;
var i;

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

// For each simulated datum, update the sum...
for ( i = 0; i < 100; i++ ) {
    if ( randu() < 0.2 ) {
        v = NaN;
    } else {
        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.

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License

See LICENSE.

Copyright

Copyright © 2016-2021. The Stdlib Authors.