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Add iterator utility to iteratively compute a cumulative geometric mean
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‎lib/node_modules/@stdlib/stats/iter/cugmean/README.md‎

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<!--
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@license Apache-2.0
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Copyright (c) 2019 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# itercugmean
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> Create an [iterator][mdn-iterator-protocol] which iteratively computes a cumulative [geometric mean][geometric-mean].
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<section class="intro">
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The [geometric mean][geometric-mean] is defined as the nth root of a product of _n_ numbers.
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<!-- <equation class="equation" label="eq:geometric_mean" align="center" raw="\biggl( \prod_{i=0}^{n-1} \biggr)^{\frac{1}{n}} = \sqrt[n]{x_0 x_1 \cdots x_{n-1}}" alt="Equation for the geometric mean."> -->
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<div class="equation" align="center" data-raw-text="\biggl( \prod_{i=0}^{n-1} \biggr)^{\frac{1}{n}} = \sqrt[n]{x_0 x_1 \cdots x_{n-1}}" data-equation="eq:geometric_mean">
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<img src="" alt="Equation for the geometric mean.">
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<br>
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</div>
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<!-- </equation> -->
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</section>
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<!-- /.intro -->
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<!-- Package usage documentation. -->
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<section class="usage">
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## Usage
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```javascript
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var itercugmean = require( '@stdlib/stats/iter/cugmean' );
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```
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#### itercugmean( iterator )
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Returns an [iterator][mdn-iterator-protocol] which iteratively computes a cumulative [geometric mean][geometric-mean].
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```javascript
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var array2iterator = require( '@stdlib/array/to-iterator' );
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var arr = array2iterator( [ 2.0, 1.0, 3.0, 7.0, 5.0 ] );
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var it = itercugmean( arr );
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var v = it.next().value;
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// returns 2.0
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v = it.next().value;
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// returns ~1.41
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v = it.next().value;
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// returns ~1.82
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v = it.next().value;
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// returns ~2.55
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v = it.next().value;
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// returns ~2.91
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```
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</section>
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<!-- /.usage -->
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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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## Notes
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- If an iterated value is non-numeric (including `NaN`) or negative, the function returns `NaN` for **all** future iterations. If non-numeric and/or negative iterated values are possible, you are advised to provide an [`iterator`][mdn-iterator-protocol] which type checks and handles such values accordingly.
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</section>
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<!-- /.notes -->
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<!-- Package usage examples. -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var runif = require( '@stdlib/random/iter/uniform' );
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var itercugmean = require( '@stdlib/stats/iter/cugmean' );
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// Create an iterator for generating uniformly distributed pseudorandom numbers:
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var rand = runif( 0.0, 10.0, {
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'seed': 1234,
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'iter': 100
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});
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// Create an iterator for iteratively computing a cumulative geometric mean:
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var it = itercugmean( rand );
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// Perform manual iteration...
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var v;
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while ( true ) {
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v = it.next();
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if ( typeof v.value === 'number' ) {
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console.log( 'gmean: %d', v.value );
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}
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if ( v.done ) {
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break;
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}
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}
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```
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</section>
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<!-- /.examples -->
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<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="references">
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</section>
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<!-- /.references -->
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<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="links">
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[geometric-mean]: https://en.wikipedia.org/wiki/Geometric_mean
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[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol
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</section>
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<!-- /.links -->

‎lib/node_modules/@stdlib/stats/iter/cugmean/benchmark/benchmark.js‎

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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2019 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var bench = require( '@stdlib/bench' );
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var isnan = require( '@stdlib/math/base/assert/is-nan' );
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var isIteratorLike = require( '@stdlib/assert/is-iterator-like' );
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var randu = require( '@stdlib/random/iter/randu' );
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var pkg = require( './../package.json' ).name;
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var itercugmean = require( './../lib' );
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// MAIN //
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bench( pkg, function benchmark( b ) {
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var rand;
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var iter;
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var i;
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rand = randu();
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b.tic();
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for ( i = 0; i < b.iterations; i++ ) {
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iter = itercugmean( rand );
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if ( typeof iter !== 'object' ) {
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b.fail( 'should return an object' );
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}
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}
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b.toc();
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if ( !isIteratorLike( iter ) ) {
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b.fail( 'should return an iterator protocol-compliant object' );
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}
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b.pass( 'benchmark finished' );
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b.end();
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});
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bench( pkg+'::iteration', function benchmark( b ) {
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var iter;
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var rand;
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var v;
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var i;
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rand = randu();
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iter = itercugmean( rand );
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b.tic();
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for ( i = 0; i < b.iterations; i++ ) {
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v = iter.next().value;
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if ( isnan( v ) ) {
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b.fail( 'should not return NaN' );
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}
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}
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b.toc();
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if ( isnan( v ) ) {
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b.fail( 'should not return NaN' );
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}
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b.pass( 'benchmark finished' );
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b.end();
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});

‎lib/node_modules/@stdlib/stats/iter/cugmean/docs/repl.txt‎

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{{alias}}( iterator )
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Returns an iterator which iteratively computes a cumulative geometric mean.
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If provided a negative value, the iterated value is `NaN` for all future
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invocations.
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If an environment supports Symbol.iterator, the returned iterator is
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iterable.
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Parameters
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----------
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iterator: Object
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Input iterator.
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Returns
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-------
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iterator: Object
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Iterator.
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iterator.next(): Function
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Returns an iterator protocol-compliant object containing the next
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iterated value (if one exists) and a boolean flag indicating whether the
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iterator is finished.
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iterator.return( [value] ): Function
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Finishes an iterator and returns a provided value.
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Examples
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--------
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> var arr = {{alias:@stdlib/array/to-iterator}}( [ 2.0, 5.0, 3.0, 5.0 ] );
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> var it = {{alias}}( arr );
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> var v = it.next().value
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2.0
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> v = it.next().value
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~3.16
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> v = it.next().value
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~3.11
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> v = it.next().value
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~3.50
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See Also
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--------
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‎lib/node_modules/@stdlib/stats/iter/cugmean/examples/index.js‎

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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2019 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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var runif = require( '@stdlib/random/iter/uniform' );
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var itercugmean = require( './../lib' );
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// Create an iterator for generating uniformly distributed pseudorandom numbers:
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var rand = runif( 0.0, 10.0, {
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'seed': 1234,
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'iter': 100
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});
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// Create an iterator for iteratively computing a cumulative geometric mean:
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var it = itercugmean( rand );
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// Perform manual iteration...
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var v;
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while ( true ) {
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v = it.next();
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if ( typeof v.value === 'number' ) {
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console.log( 'gmean: %d', v.value );
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}
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if ( v.done ) {
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break;
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}
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}

‎lib/node_modules/@stdlib/stats/iter/cugmean/lib/index.js‎

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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2019 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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/**
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* Create an iterator which iteratively computes a cumulative geometric mean.
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*
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* @module @stdlib/stats/iter/cugmean
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*
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* @example
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* var runif = require( '@stdlib/random/iter/uniform' );
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* var itercugmean = require( '@stdlib/stats/iter/cugmean' );
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*
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* var rand = runif( 0.0, 10.0, {
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* 'iter': 100
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* });
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*
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* var it = itercugmean( rand );
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*
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* var v = it.next().value;
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* // returns <number>
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*
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* v = it.next().value;
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* // returns <number>
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*
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* v = it.next().value;
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* // returns <number>
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*
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* // ...
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*/
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// MODULES //
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var iterator = require( './main.js' );
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// EXPORTS //
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module.exports = iterator;

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