From 78a512da05e93e2d1690b100ab04c73605b7461b Mon Sep 17 00:00:00 2001 From: Sachin Pangal Date: Thu, 6 Nov 2025 22:38:05 +0530 Subject: [PATCH 01/10] feat: add stats/base/ndarray/meanwd --- .../stats/base/ndarray/meanwd/README.md | 143 +++++++++++++++ .../ndarray/meanwd/benchmark/benchmark.js | 102 +++++++++++ .../docs/img/equation_arithmetic_mean.svg | 42 +++++ .../stats/base/ndarray/meanwd/docs/repl.txt | 32 ++++ .../base/ndarray/meanwd/docs/types/index.d.ts | 45 +++++ .../base/ndarray/meanwd/docs/types/test.ts | 57 ++++++ .../base/ndarray/meanwd/examples/index.js | 0 .../stats/base/ndarray/meanwd/lib/index.js | 44 +++++ .../stats/base/ndarray/meanwd/lib/main.js | 55 ++++++ .../stats/base/ndarray/meanwd/package.json | 67 +++++++ .../stats/base/ndarray/meanwd/test/test.js | 172 ++++++++++++++++++ 11 files changed, 759 insertions(+) create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/benchmark/benchmark.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/img/equation_arithmetic_mean.svg create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/repl.txt create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/index.d.ts create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/test.ts create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/index.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/main.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/package.json create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/meanwd/test/test.js diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md new file mode 100644 index 000000000000..8a2adad90658 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -0,0 +1,143 @@ + + +# meanwd + +> Compute the [arithmetic mean][arithmetic-mean] of a one-dimensional ndarray using Welford's algorithm. + +
+ +The [arithmetic mean][arithmetic-mean] is defined as + + + +```math +\mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i +``` + + + + + +
+ + + +
+ +## Usage + +```javascript +var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); +``` + +#### meanwd( arrays ) + +Computes the [arithmetic mean][arithmetic-mean] of a one-dimensional ndarray using Welford's algorithm. + +```javascript +var ndarray = require( '@stdlib/ndarray/base/ctor' ); + +var xbuf = [ 1.0, 3.0, 4.0, 2.0 ]; +var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' ); + +var v = meanwd( [ x ] ); +// returns 2.5 +``` + +The function has the following parameters: + +- **arrays**: array-like object containing a one-dimensional input ndarray. + +
+ + + +
+ +## Notes + +- If provided an empty one-dimensional ndarray, the function returns `NaN`. +- This implementation uses Welford's algorithm for efficient computation, which can be derived as follows + + ```tex + \begin{align*} + \mu_n &= \frac{1}{n} \sum_{i=0}^{n-1} x_i \\ + &= \frac{1}{n} \biggl(x_{n-1} + \sum_{i=0}^{n-2} x_i \biggr) \\ + &= \frac{1}{n} (x_{n-1} + (n-1)\mu_{n-1}) \\ + &= \mu_{n-1} + \frac{1}{n} (x_{n-1} - \mu_{n-1}) + \end{align*} + ``` + +## References + +- Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022](https://doi.org/10.1080/00401706.1962.10490022). +- van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961). + +
+ + + +
+ +## Examples + + + +```javascript +var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var ndarray2array = require( '@stdlib/ndarray/to-array' ); +var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); + +var xbuf = discreteUniform( 10, -50, 50, { + 'dtype': 'generic' +}); +var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' ); +console.log( ndarray2array( x ) ); + +var v = meanwd( [ x ] ); +console.log( v ); +``` + +
+ + + + + +
+ +
+ + + + + +
+ +[arithmetic-mean]: https://en.wikipedia.org/wiki/Arithmetic_mean + +
+ + diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/benchmark/benchmark.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/benchmark/benchmark.js new file mode 100644 index 000000000000..658153b1aa85 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/benchmark/benchmark.js @@ -0,0 +1,102 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +// MODULES // + +var bench = require( '@stdlib/bench' ); +var uniform = require( '@stdlib/random/array/uniform' ); +var isnan = require( '@stdlib/math/base/assert/is-nan' ); +var pow = require( '@stdlib/math/base/special/pow' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var pkg = require( './../package.json' ).name; +var meanwd = require( './../lib' ); + + +// VARIABLES // + +var options = { + 'dtype': 'generic' +}; + + +// FUNCTIONS // + +/** +* Creates a benchmark function. +* +* @private +* @param {PositiveInteger} len - array length +* @returns {Function} benchmark function +*/ +function createBenchmark( len ) { + var xbuf; + var x; + + xbuf = uniform( len, -10.0, 10.0, options ); + x = new ndarray( options.dtype, xbuf, [ len ], [ 1 ], 0, 'row-major' ); + + return benchmark; + + function benchmark( b ) { + var v; + var i; + + b.tic(); + for ( i = 0; i < b.iterations; i++ ) { + v = meanwd( [ x ] ); + if ( isnan( v ) ) { + b.fail( 'should not return NaN' ); + } + } + b.toc(); + if ( isnan( v ) ) { + b.fail( 'should not return NaN' ); + } + b.pass( 'benchmark finished' ); + b.end(); + } +} + + +// MAIN // + +/** +* Main execution sequence. +* +* @private +*/ +function main() { + var len; + var min; + var max; + var f; + var i; + + min = 1; // 10^min + max = 6; // 10^max + + for ( i = min; i <= max; i++ ) { + len = pow( 10, i ); + f = createBenchmark( len ); + bench( pkg+':len='+len, f ); + } +} + +main(); diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/img/equation_arithmetic_mean.svg b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/img/equation_arithmetic_mean.svg new file mode 100644 index 000000000000..c31439606fb6 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/img/equation_arithmetic_mean.svg @@ -0,0 +1,42 @@ + +mu equals StartFraction 1 Over n EndFraction sigma-summation Underscript i equals 0 Overscript n minus 1 Endscripts x Subscript i + + + \ No newline at end of file diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/repl.txt b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/repl.txt new file mode 100644 index 000000000000..2c4bfa981d3f --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/repl.txt @@ -0,0 +1,32 @@ + +{{alias}}( arrays ) + Computes the arithmetic mean of a one-dimensional ndarray using Welford's + algorithm. + + If provided an empty ndarray, the function returns `NaN`. + + Parameters + ---------- + arrays: ArrayLikeObject + Array-like object containing a one-dimensional input ndarray. + + Returns + ------- + out: number + Arithmetic mean. + + Examples + -------- + > var xbuf = [ 1.0, -2.0, 2.0 ]; + > var dt = 'generic'; + > var sh = [ xbuf.length ]; + > var sx = [ 1 ]; + > var ox = 0; + > var ord = 'row-major'; + > var x = new {{alias:@stdlib/ndarray/ctor}}( dt, xbuf, sh, sx, ox, ord ); + > {{alias}}( [ x ] ) + ~0.3333 + + See Also + -------- + diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/index.d.ts b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/index.d.ts new file mode 100644 index 000000000000..8fb425892077 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/index.d.ts @@ -0,0 +1,45 @@ +/* +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +// TypeScript Version: 4.1 + +/// + +import { ndarray } from '@stdlib/types/ndarray'; + +/** +* Computes the arithmetic mean of a one-dimensional ndarray using Welford's algorithm. +* +* @param arrays - array-like object containing an input ndarray +* @returns arithmetic mean +* +* @example +* var ndarray = require( '@stdlib/ndarray/base/ctor' ); +* +* var xbuf = [ 1.0, 3.0, 4.0, 2.0 ]; +* var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' ); +* +* var v = meanwd( [ x ] ); +* // returns 2.5 +*/ +declare function meanwd( arrays: [ T ] ): number; + + +// EXPORTS // + +export = meanwd; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/test.ts b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/test.ts new file mode 100644 index 000000000000..722cc4a4f591 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/docs/types/test.ts @@ -0,0 +1,57 @@ +/* +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +/* eslint-disable space-in-parens */ + +import zeros = require( '@stdlib/ndarray/zeros' ); +import meanwd = require( './index' ); + + +// TESTS // + +// The function returns a number... +{ + const x = zeros( [ 10 ], { + 'dtype': 'generic' + }); + + meanwd( [ x ] ); // $ExpectType number +} + +// The compiler throws an error if the function is provided a first argument which is not an array of ndarrays... +{ + meanwd( '10' ); // $ExpectError + meanwd( 10 ); // $ExpectError + meanwd( true ); // $ExpectError + meanwd( false ); // $ExpectError + meanwd( null ); // $ExpectError + meanwd( undefined ); // $ExpectError + meanwd( [] ); // $ExpectError + meanwd( {} ); // $ExpectError + meanwd( ( x: number ): number => x ); // $ExpectError +} + +// The compiler throws an error if the function is provided an unsupported number of arguments... +{ + const x = zeros( [ 10 ], { + 'dtype': 'generic' + }); + + meanwd(); // $ExpectError + meanwd( [ x ], {} ); // $ExpectError +} diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js new file mode 100644 index 000000000000..e69de29bb2d1 diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/index.js new file mode 100644 index 000000000000..fb8813029869 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/index.js @@ -0,0 +1,44 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +/** +* Compute the arithmetic mean of a one-dimensional ndarray using Welford's algorithm. +* +* @module @stdlib/stats/base/ndarray/meanwd +* +* @example +* var ndarray = require( '@stdlib/ndarray/base/ctor' ); +* var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); +* +* var xbuf = [ 1.0, 3.0, 4.0, 2.0 ]; +* var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' ); +* +* var v = meanwd( [ x ] ); +* // returns 2.5 +*/ + +// MODULES // + +var main = require( './main.js' ); + + +// EXPORTS // + +module.exports = main; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/main.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/main.js new file mode 100644 index 000000000000..7b9d92530f90 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/lib/main.js @@ -0,0 +1,55 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +// MODULES // + +var numelDimension = require( '@stdlib/ndarray/base/numel-dimension' ); +var getStride = require( '@stdlib/ndarray/base/stride' ); +var getOffset = require( '@stdlib/ndarray/base/offset' ); +var getData = require( '@stdlib/ndarray/base/data-buffer' ); +var strided = require( '@stdlib/stats/strided/meanwd' ).ndarray; + + +// MAIN // + +/** +* Computes the arithmetic mean of a one-dimensional ndarray using Welford's algorithm. +* +* @param {ArrayLikeObject} arrays - array-like object containing an input ndarray +* @returns {number} arithmetic mean +* +* @example +* var ndarray = require( '@stdlib/ndarray/base/ctor' ); +* +* var xbuf = [ 1.0, 3.0, 4.0, 2.0 ]; +* var x = new ndarray( 'generic', xbuf, [ 4 ], [ 1 ], 0, 'row-major' ); +* +* var v = meanwd( [ x ] ); +* // returns 2.5 +*/ +function meanwd( arrays ) { + var x = arrays[ 0 ]; + return strided( numelDimension( x, 0 ), getData( x ), getStride( x, 0 ), getOffset( x ) ); // eslint-disable-line max-len +} + + +// EXPORTS // + +module.exports = meanwd; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/package.json b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/package.json new file mode 100644 index 000000000000..579a897af945 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/package.json @@ -0,0 +1,67 @@ +{ + "name": "@stdlib/stats/base/ndarray/meanwd", + "version": "0.0.0", + "description": "Compute the arithmetic mean of a one-dimensional ndarray using Welford's algorithm.", + "license": "Apache-2.0", + "author": { + "name": "The Stdlib Authors", + "url": "https://github.com/stdlib-js/stdlib/graphs/contributors" + }, + "contributors": [ + { + "name": "The Stdlib Authors", + "url": "https://github.com/stdlib-js/stdlib/graphs/contributors" + } + ], + "main": "./lib", + "directories": { + "benchmark": "./benchmark", + "doc": "./docs", + "example": "./examples", + "lib": "./lib", + "test": "./test" + }, + "types": "./docs/types", + "scripts": {}, + "homepage": "https://github.com/stdlib-js/stdlib", + "repository": { + "type": "git", + "url": "git://github.com/stdlib-js/stdlib.git" + }, + "bugs": { + "url": "https://github.com/stdlib-js/stdlib/issues" + }, + "dependencies": {}, + "devDependencies": {}, + "engines": { + "node": ">=0.10.0", + "npm": ">2.7.0" + }, + "os": [ + "aix", + "darwin", + "freebsd", + "linux", + "macos", + "openbsd", + "sunos", + "win32", + "windows" + ], + "keywords": [ + "stdlib", + "stdmath", + "statistics", + "stats", + "mathematics", + "math", + "average", + "avg", + "mean", + "arithmetic mean", + "central tendency", + "welford", + "ndarray" + ], + "__stdlib__": {} +} diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/test/test.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/test/test.js new file mode 100644 index 000000000000..0aa452d77eda --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/test/test.js @@ -0,0 +1,172 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +// MODULES // + +var tape = require( 'tape' ); +var isnan = require( '@stdlib/math/base/assert/is-nan' ); +var isPositiveZero = require( '@stdlib/math/base/assert/is-positive-zero' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var meanwd = require( './../lib' ); + + +// FUNCTIONS // + +/** +* Returns a one-dimensional ndarray. +* +* @private +* @param {Collection} buffer - underlying data buffer +* @param {NonNegativeInteger} length - number of indexed elements +* @param {integer} stride - stride length +* @param {NonNegativeInteger} offset - index offset +* @returns {ndarray} one-dimensional ndarray +*/ +function vector( buffer, length, stride, offset ) { + return new ndarray( 'generic', buffer, [ length ], [ stride ], offset, 'row-major' ); +} + + +// TESTS // + +tape( 'main export is a function', function test( t ) { + t.ok( true, __filename ); + t.strictEqual( typeof meanwd, 'function', 'main export is a function' ); + t.end(); +}); + +tape( 'the function has an arity of 1', function test( t ) { + t.strictEqual( meanwd.length, 1, 'has expected arity' ); + t.end(); +}); + +tape( 'the function calculates the arithmetic mean of a one-dimensional ndarray', function test( t ) { + var x; + var v; + + x = [ 1.0, -2.0, -4.0, 5.0, 0.0, 3.0 ]; + v = meanwd( [ vector( x, 6, 1, 0 ) ] ); + t.strictEqual( v, 0.5, 'returns expected value' ); + + x = [ -4.0, -5.0 ]; + v = meanwd( [ vector( x, 2, 1, 0 ) ] ); + t.strictEqual( v, -4.5, 'returns expected value' ); + + x = [ -0.0, 0.0, -0.0 ]; + v = meanwd( [ vector( x, 3, 1, 0 ) ] ); + t.strictEqual( isPositiveZero( v ), true, 'returns expected value' ); + + x = [ NaN ]; + v = meanwd( [ vector( x, 1, 1, 0 ) ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + x = [ NaN, NaN ]; + v = meanwd( [ vector( x, 2, 1, 0 ) ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + t.end(); +}); + +tape( 'if provided an empty vector, the function returns `NaN`', function test( t ) { + var x; + var v; + + x = []; + + v = meanwd( [ vector( x, 0, 1, 0 ) ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + t.end(); +}); + +tape( 'if provided a vector containing a single element, the function returns that element', function test( t ) { + var x; + var v; + + x = [ 1.0 ]; + + v = meanwd( [ vector( x, 1, 1, 0 ) ] ); + t.strictEqual( v, 1.0, 'returns expected value' ); + + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having non-unit strides', function test( t ) { + var x; + var v; + + x = [ + 1.0, // 0 + 2.0, + 2.0, // 1 + -7.0, + -2.0, // 2 + 3.0, + 4.0, // 3 + 2.0 + ]; + + v = meanwd( [ vector( x, 4, 2, 0 ) ] ); + + t.strictEqual( v, 1.25, 'returns expected value' ); + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having negative strides', function test( t ) { + var x; + var v; + + x = [ + 1.0, // 3 + 2.0, + 2.0, // 2 + -7.0, + -2.0, // 1 + 3.0, + 4.0, // 0 + 2.0 + ]; + + v = meanwd( [ vector( x, 4, -2, 6 ) ] ); + + t.strictEqual( v, 1.25, 'returns expected value' ); + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having non-zero offsets', function test( t ) { + var x; + var v; + + x = [ + 2.0, + 1.0, // 0 + 2.0, + -2.0, // 1 + -2.0, + 2.0, // 2 + 3.0, + 4.0 // 3 + ]; + + v = meanwd( [ vector( x, 4, 2, 1 ) ] ); + t.strictEqual( v, 1.25, 'returns expected value' ); + + t.end(); +}); From d4565ec3f88ddad874354149396e6671aac4d1df Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 22:52:21 +0530 Subject: [PATCH 02/10] Refactor README.md for meanwd function Updated README.md for meanwd function to improve clarity and formatting. Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> --- .../@stdlib/stats/base/ndarray/meanwd/README.md | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index 8a2adad90658..fd11145e467b 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -27,7 +27,6 @@ limitations under the License. The [arithmetic mean][arithmetic-mean] is defined as - ```math \mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i ``` @@ -46,7 +45,6 @@ The [arithmetic mean][arithmetic-mean] is defined as
## Usage - ```javascript var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); ``` @@ -54,7 +52,6 @@ var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); #### meanwd( arrays ) Computes the [arithmetic mean][arithmetic-mean] of a one-dimensional ndarray using Welford's algorithm. - ```javascript var ndarray = require( '@stdlib/ndarray/base/ctor' ); @@ -78,20 +75,21 @@ The function has the following parameters: ## Notes - If provided an empty one-dimensional ndarray, the function returns `NaN`. -- This implementation uses Welford's algorithm for efficient computation, which can be derived as follows - ```tex +- This implementation uses Welford's algorithm for efficient computation, which can be derived as follows +```tex \begin{align*} \mu_n &= \frac{1}{n} \sum_{i=0}^{n-1} x_i \\ &= \frac{1}{n} \biggl(x_{n-1} + \sum_{i=0}^{n-2} x_i \biggr) \\ &= \frac{1}{n} (x_{n-1} + (n-1)\mu_{n-1}) \\ &= \mu_{n-1} + \frac{1}{n} (x_{n-1} - \mu_{n-1}) \end{align*} - ``` +``` ## References - Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022](https://doi.org/10.1080/00401706.1962.10490022). + - van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961).
@@ -103,7 +101,6 @@ The function has the following parameters: ## Examples - ```javascript var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); var ndarray = require( '@stdlib/ndarray/base/ctor' ); From eee9ad01dfba716ca16feca6467e7bb8ac8cf162 Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 22:55:52 +0530 Subject: [PATCH 03/10] Add example for meanwd function Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> --- .../base/ndarray/meanwd/examples/index.js | 33 +++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js index e69de29bb2d1..21f568ad0c40 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js @@ -0,0 +1,33 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var ndarray2array = require( '@stdlib/ndarray/to-array' ); +var meanwd = require( './../lib' ); + +var xbuf = discreteUniform( 10, -50, 50, { + 'dtype': 'generic' +}); +var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' ); +console.log( ndarray2array( x ) ); + +var v = meanwd( [ x ] ); +console.log( v ); From 4cf115dad3b99b9bd093e814610f05785bf02973 Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 23:04:50 +0530 Subject: [PATCH 04/10] Update license header and formatting in example Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> From 6458f8a1bb370c12d74b5d920c86936fabfc5a30 Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 23:13:15 +0530 Subject: [PATCH 05/10] Update license header in index.js example Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> --- .../@stdlib/stats/base/ndarray/meanwd/examples/index.js | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js index 21f568ad0c40..fdee1f3a8be2 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js @@ -31,3 +31,4 @@ console.log( ndarray2array( x ) ); var v = meanwd( [ x ] ); console.log( v ); + From a8881a26135510b3993301e9fe9f103cf368811a Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 23:14:24 +0530 Subject: [PATCH 06/10] Enhance README with math representation and examples Updated README.md to include a mathematical representation of the arithmetic mean and improved usage examples. Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> --- .../@stdlib/stats/base/ndarray/meanwd/README.md | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index fd11145e467b..047dbab71257 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -27,6 +27,7 @@ limitations under the License. The [arithmetic mean][arithmetic-mean] is defined as + ```math \mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i ``` @@ -45,6 +46,7 @@ The [arithmetic mean][arithmetic-mean] is defined as
## Usage + ```javascript var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); ``` @@ -52,6 +54,7 @@ var meanwd = require( '@stdlib/stats/base/ndarray/meanwd' ); #### meanwd( arrays ) Computes the [arithmetic mean][arithmetic-mean] of a one-dimensional ndarray using Welford's algorithm. + ```javascript var ndarray = require( '@stdlib/ndarray/base/ctor' ); @@ -77,6 +80,7 @@ The function has the following parameters: - If provided an empty one-dimensional ndarray, the function returns `NaN`. - This implementation uses Welford's algorithm for efficient computation, which can be derived as follows + ```tex \begin{align*} \mu_n &= \frac{1}{n} \sum_{i=0}^{n-1} x_i \\ @@ -89,8 +93,7 @@ The function has the following parameters: ## References - Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022](https://doi.org/10.1080/00401706.1962.10490022). - -- van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961). + - van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961).
@@ -101,6 +104,7 @@ The function has the following parameters: ## Examples + ```javascript var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); var ndarray = require( '@stdlib/ndarray/base/ctor' ); From e8c3f6bff0b02d995d7c541538ec7dcb072e41dd Mon Sep 17 00:00:00 2001 From: Sachin Pangal Date: Thu, 6 Nov 2025 23:35:26 +0530 Subject: [PATCH 07/10] fix: normalize LF line endings and fix README list formatting in meanwd - Convert examples/index.js to LF line endings (remove CRLF) - Remove extra blank line between list items in README.md - Fix indentation of second reference item in README.md --- .../stats/base/ndarray/meanwd/README.md | 5 +- .../base/ndarray/meanwd/examples/index.js | 67 +++++++++---------- 2 files changed, 35 insertions(+), 37 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index 047dbab71257..e2a65dc9f25f 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -78,7 +78,6 @@ The function has the following parameters: ## Notes - If provided an empty one-dimensional ndarray, the function returns `NaN`. - - This implementation uses Welford's algorithm for efficient computation, which can be derived as follows ```tex @@ -93,7 +92,7 @@ The function has the following parameters: ## References - Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022](https://doi.org/10.1080/00401706.1962.10490022). - - van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961). +- van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961). @@ -141,4 +140,4 @@ console.log( v ); - + \ No newline at end of file diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js index fdee1f3a8be2..a63add27f092 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/examples/index.js @@ -1,34 +1,33 @@ -/** -* @license Apache-2.0 -* -* Copyright (c) 2025 The Stdlib Authors. -* -* Licensed under the Apache License, Version 2.0 (the "License"); -* you may not use this file except in compliance with the License. -* You may obtain a copy of the License at -* -* http://www.apache.org/licenses/LICENSE-2.0 -* -* Unless required by applicable law or agreed to in writing, software -* distributed under the License is distributed on an "AS IS" BASIS, -* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -* See the License for the specific language governing permissions and -* limitations under the License. -*/ - -'use strict'; - -var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); -var ndarray = require( '@stdlib/ndarray/base/ctor' ); -var ndarray2array = require( '@stdlib/ndarray/to-array' ); -var meanwd = require( './../lib' ); - -var xbuf = discreteUniform( 10, -50, 50, { - 'dtype': 'generic' -}); -var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' ); -console.log( ndarray2array( x ) ); - -var v = meanwd( [ x ] ); -console.log( v ); - +/** +* @license Apache-2.0 +* +* Copyright (c) 2025 The Stdlib Authors. +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +'use strict'; + +var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var ndarray2array = require( '@stdlib/ndarray/to-array' ); +var meanwd = require( './../lib' ); + +var xbuf = discreteUniform( 10, -50, 50, { + 'dtype': 'generic' +}); +var x = new ndarray( 'generic', xbuf, [ xbuf.length ], [ 1 ], 0, 'row-major' ); +console.log( ndarray2array( x ) ); + +var v = meanwd( [ x ] ); +console.log( v ); From d4aca2047b2c15867675f1dad8c83bbc309f83e2 Mon Sep 17 00:00:00 2001 From: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> Date: Thu, 6 Nov 2025 23:42:44 +0530 Subject: [PATCH 08/10] Fix missing newline at end of README.md Signed-off-by: Sachin Pangal <151670745+Orthodox-64@users.noreply.github.com> --- lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index e2a65dc9f25f..5e1bb2f813d0 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -140,4 +140,4 @@ console.log( v ); - \ No newline at end of file + From 45050cf2475bdbe60f7b7c16c8c89f5183860fe0 Mon Sep 17 00:00:00 2001 From: Athan Date: Thu, 6 Nov 2025 13:29:00 -0800 Subject: [PATCH 09/10] docs: remove note Signed-off-by: Athan --- .../@stdlib/stats/base/ndarray/meanwd/README.md | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index 5e1bb2f813d0..ed6dbd3d83b2 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -78,16 +78,6 @@ The function has the following parameters: ## Notes - If provided an empty one-dimensional ndarray, the function returns `NaN`. -- This implementation uses Welford's algorithm for efficient computation, which can be derived as follows - -```tex - \begin{align*} - \mu_n &= \frac{1}{n} \sum_{i=0}^{n-1} x_i \\ - &= \frac{1}{n} \biggl(x_{n-1} + \sum_{i=0}^{n-2} x_i \biggr) \\ - &= \frac{1}{n} (x_{n-1} + (n-1)\mu_{n-1}) \\ - &= \mu_{n-1} + \frac{1}{n} (x_{n-1} - \mu_{n-1}) - \end{align*} -``` ## References From 484b61eede4cf80567636d5b52fa43340af6da92 Mon Sep 17 00:00:00 2001 From: Athan Date: Thu, 6 Nov 2025 13:34:04 -0800 Subject: [PATCH 10/10] docs: fix references Signed-off-by: Athan --- .../stats/base/ndarray/meanwd/README.md | 26 ++++++++++++++----- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md index ed6dbd3d83b2..ff937c4496ec 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/meanwd/README.md @@ -79,11 +79,6 @@ The function has the following parameters: - If provided an empty one-dimensional ndarray, the function returns `NaN`. -## References - -- Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022](https://doi.org/10.1080/00401706.1962.10490022). -- van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961](https://doi.org/10.1145/362929.362961). - @@ -92,8 +87,8 @@ The function has the following parameters: ## Examples - - + + ```javascript var discreteUniform = require( '@stdlib/random/array/discrete-uniform' ); var ndarray = require( '@stdlib/ndarray/base/ctor' ); @@ -114,6 +109,19 @@ console.log( v ); +* * * + +
+ +## References + +- Welford, B. P. 1962. "Note on a Method for Calculating Corrected Sums of Squares and Products." _Technometrics_ 4 (3). Taylor & Francis: 419–20. doi:[10.1080/00401706.1962.10490022][@welford:1962a]. +- van Reeken, A. J. 1968. "Letters to the Editor: Dealing with Neely's Algorithms." _Communications of the ACM_ 11 (3): 149–50. doi:[10.1145/362929.362961][@vanreeken:1968a]. + +
+ + +
@@ -128,6 +136,10 @@ console.log( v ); [arithmetic-mean]: https://en.wikipedia.org/wiki/Arithmetic_mean +[@welford:1962a]: https://doi.org/10.1080/00401706.1962.10490022 + +[@vanreeken:1968a]: https://doi.org/10.1145/362929.362961 +