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itermmean
Create an iterator which iteratively computes a moving arithmetic mean.
For a window of size W
, the arithmetic mean is defined as
Installation
npm install @stdlib/statsitermmean
Usage
var itermmean = require( '@stdlib/statsitermmean' );
itermmean( iterator, W )
Returns an iterator which iteratively computes a moving arithmetic mean. The W
parameter defines the number of iterated values over which to compute the moving mean.
var array2iterator = require( '@stdlib/arraytoiterator' );
var arr = array2iterator( [ 2.0, 1.0, 3.0, 7.0, 5.0 ] );
var it = itermmean( arr, 3 );
// Fill the window...
var m = it.next().value; // [2.0]
// returns 2.0
m = it.next().value; // [2.0, 1.0]
// returns 1.5
m = it.next().value; // [2.0, 1.0, 3.0]
// returns 2.0
// Window begins sliding...
m = it.next().value; // [1.0, 3.0, 7.0]
// returns 1.0
m = it.next().value; // [3.0, 7.0, 5.0]
// returns 3.0
Notes
 If an iterated value is nonnumeric (including
NaN
), the function returnsNaN
for at leastW1
future invocations. If nonnumeric iterated values are possible, you are advised to provide aniterator
which type checks and handles nonnumeric values accordingly.  As
W
values are needed to fill the window buffer, the firstW1
returned values are calculated from smaller sample sizes. Until the window is full, each returned value is calculated from all previously iterated values.
Examples
var runif = require( '@stdlib/randomiteruniform' );
var itermmean = require( '@stdlib/statsitermmean' );
// Create an iterator for generating uniformly distributed pseudorandom numbers:
var rand = runif( 10.0, 10.0, {
'seed': 1234,
'iter': 100
});
// Create an iterator for iteratively computing a moving arithmetic mean:
var it = itermmean( rand, 3 );
// Perform manual iteration...
var v;
while ( true ) {
v = it.next();
if ( v.done ) {
break;
}
if ( typeof v.value === 'number' ) {
console.log( 'Mean: %d', v.value );
}
}
See Also

@stdlib/statsiter/mean
: compute the arithmetic mean over all iterated values. 
@stdlib/statsiter/msum
: create an iterator which iteratively computes a moving sum.
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.
Community
License
See LICENSE.
Copyright
Copyright © 20162024. The Stdlib Authors.