From 5121f44603cd8b0f806db03e75d20431d93b8032 Mon Sep 17 00:00:00 2001 From: iampratik13 Date: Sun, 9 Aug 2026 15:37:37 +0530 Subject: [PATCH 1/2] feat: stats/base/ndarray/dvariancech --- type: pre_commit_static_analysis_report description: Results of running static analysis checks when committing changes. report: - task: lint_filenames status: passed - task: lint_editorconfig status: passed - task: lint_markdown_pkg_readmes status: passed - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: passed - task: lint_repl_help status: passed - task: lint_javascript_src status: passed - task: lint_javascript_cli status: na - task: lint_javascript_examples status: passed - task: lint_javascript_tests status: passed - task: lint_javascript_benchmarks status: passed - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - task: lint_c_tests_fixtures status: na - task: lint_shell status: na - task: lint_typescript_declarations status: passed - task: lint_typescript_tests status: passed - task: lint_license_headers status: passed --- --- .../stats/base/ndarray/dvariancech/README.md | 211 ++++++++++++++++ .../dvariancech/benchmark/benchmark.js | 109 +++++++++ .../docs/img/equation_sample_mean.svg | 43 ++++ .../base/ndarray/dvariancech/docs/repl.txt | 44 ++++ .../ndarray/dvariancech/docs/types/index.d.ts | 57 +++++ .../ndarray/dvariancech/docs/types/test.ts | 64 +++++ .../ndarray/dvariancech/examples/index.js | 35 +++ .../base/ndarray/dvariancech/lib/index.js | 49 ++++ .../base/ndarray/dvariancech/lib/main.js | 74 ++++++ .../base/ndarray/dvariancech/package.json | 75 ++++++ .../base/ndarray/dvariancech/test/test.js | 227 ++++++++++++++++++ 11 files changed, 988 insertions(+) create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/benchmark/benchmark.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/img/equation_sample_mean.svg create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/repl.txt create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/index.d.ts create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/test.ts create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/examples/index.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/index.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/main.js create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/package.json create mode 100644 lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/test/test.js diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md new file mode 100644 index 000000000000..7326c37513b4 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md @@ -0,0 +1,211 @@ + + +# dvariancech + +> Calculate the [variance][variance] of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean algorithm. + +
+ +The population [variance][variance] of a finite size population of size `N` is given by + + + +```math +\sigma^2 = \frac{1}{N} \sum_{i=0}^{N-1} (x_i - \mu)^2 +``` + + + + + +where the population mean is given by + + + +```math +\mu = \frac{1}{N} \sum_{i=0}^{N-1} x_i +``` + + + + + +Often in the analysis of data, the true population [variance][variance] is not known _a priori_ and must be estimated from a sample drawn from the population distribution. If one attempts to use the formula for the population [variance][variance], the result is biased and yields an **uncorrected sample variance**. To compute a **corrected sample variance** for a sample of size `n`, + + + +```math +s^2 = \frac{1}{n-1} \sum_{i=0}^{n-1} (x_i - \bar{x})^2 +``` + + + + + +where the sample mean is given by + + + +```math +\bar{x} = \frac{1}{n} \sum_{i=0}^{n-1} x_i +``` + + + + + +The use of the term `n-1` is commonly referred to as Bessel's correction. Note, however, that applying Bessel's correction can increase the mean squared error between the sample variance and population variance. Depending on the characteristics of the population distribution, other correction factors (e.g., `n-1.5`, `n+1`, etc) can yield better estimators. + +
+ + + +
+ +## Usage + +```javascript +var dvariancech = require( '@stdlib/stats/base/ndarray/dvariancech' ); +``` + +#### dvariancech( arrays ) + +Computes the [variance][variance] of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean algorithm. + +```javascript +var Float64Vector = require( '@stdlib/ndarray/vector/float64' ); +var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); + +var opts = { + 'dtype': 'float64' +}; + +var x = new Float64Vector( [ 1.0, -2.0, 2.0 ] ); +var correction = scalar2ndarray( 1.0, opts ); + +var v = dvariancech( [ x, correction ] ); +// returns ~4.3333 +``` + +The function has the following parameters: + +- **arrays**: array-like object containing the following ndarrays: + + - a one-dimensional input ndarray. + - a zero-dimensional ndarray specifying the degrees of freedom adjustment. Providing a non-zero degrees of freedom adjustment has the effect of adjusting the divisor during the calculation of the [variance][variance] according to `N-c` where `N` is the number of elements in the input ndarray and `c` corresponds to the provided degrees of freedom adjustment. When computing the [variance][variance] of a population, setting this parameter to `0` is the standard choice (i.e., the provided array contains data constituting an entire population). When computing the corrected sample [variance][variance], setting this parameter to `1` is the standard choice (i.e., the provided array contains data sampled from a larger population; this is commonly referred to as Bessel's correction). + +
+ + + +
+ +## Notes + +- If provided an empty one-dimensional ndarray, the function returns `NaN`. +- If `N - c` is less than or equal to `0` (where `N` corresponds to the number of elements in the input ndarray and `c` corresponds to the provided degrees of freedom adjustment), the function returns `NaN`. + +
+ + + +
+ +## Examples + + + +```javascript +var discreteUniform = require( '@stdlib/random/discrete-uniform' ); +var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +var ndarray2array = require( '@stdlib/ndarray/to-array' ); +var dvariancech = require( '@stdlib/stats/base/ndarray/dvariancech' ); + +var opts = { + 'dtype': 'float64' +}; + +var x = discreteUniform( [ 10 ], -50, 50, opts ); +console.log( ndarray2array( x ) ); + +var correction = scalar2ndarray( 1.0, opts ); +var v = dvariancech( [ x, correction ] ); +console.log( v ); +``` + +
+ + + +* * * + +
+ +## References + +- Neely, Peter M. 1966. "Comparison of Several Algorithms for Computation of Means, Standard Deviations and Correlation Coefficients." _Communications of the ACM_ 9 (7). Association for Computing Machinery: 496–99. doi:[10.1145/365719.365958][@neely:1966a]. +- Ling, Robert F. 1974. "Comparison of Several Algorithms for Computing Sample Means and Variances." _Journal of the American Statistical Association_ 69 (348). American Statistical Association, Taylor & Francis, Ltd.: 859–66. doi:[10.2307/2286154][@ling:1974a]. +- Chan, Tony F., Gene H. Golub, and Randall J. LeVeque. 1983. "Algorithms for Computing the Sample Variance: Analysis and Recommendations." _The American Statistician_ 37 (3). American Statistical Association, Taylor & Francis, Ltd.: 242–47. doi:[10.1080/00031305.1983.10483115][@chan:1983a]. +- Schubert, Erich, and Michael Gertz. 2018. "Numerically Stable Parallel Computation of (Co-)Variance." In _Proceedings of the 30th International Conference on Scientific and Statistical Database Management_. New York, NY, USA: Association for Computing Machinery. doi:[10.1145/3221269.3223036][@schubert:2018a]. + +
+ + + + + +
+ +* * * + +
+ + + + + +
+ +[variance]: https://en.wikipedia.org/wiki/Variance + +[@neely:1966a]: https://doi.org/10.1145/365719.365958 + +[@ling:1974a]: https://doi.org/10.2307/2286154 + +[@chan:1983a]: https://doi.org/10.1080/00031305.1983.10483115 + +[@schubert:2018a]: https://doi.org/10.1145/3221269.3223036 + +
+ + diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/benchmark/benchmark.js b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/benchmark/benchmark.js new file mode 100644 index 000000000000..d630e555493f --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/benchmark/benchmark.js @@ -0,0 +1,109 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2026 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/uniform' ); +var isnan = require( '@stdlib/math/base/assert/is-nan' ); +var pow = require( '@stdlib/math/base/special/pow' ); +var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +var format = require( '@stdlib/string/format' ); +var pkg = require( './../package.json' ).name; +var dvariancech = require( './../lib' ); + + +// VARIABLES // + +var options = { + 'dtype': 'float64' +}; + + +// FUNCTIONS // + +/** +* Creates a benchmark function. +* +* @private +* @param {PositiveInteger} len - array length +* @returns {Function} benchmark function +*/ +function createBenchmark( len ) { + var correction; + var x; + + x = uniform( [ len ], -10.0, 10.0, options ); + correction = scalar2ndarray( 1.0, options ); + + return benchmark; + + /** + * Benchmark function. + * + * @private + * @param {Benchmark} b - benchmark instance + */ + function benchmark( b ) { + var v; + var i; + + b.tic(); + for ( i = 0; i < b.iterations; i++ ) { + v = dvariancech( [ x, correction ] ); + 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( format( '%s:len=%d', pkg, len ), f ); + } +} + +main(); diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/img/equation_sample_mean.svg b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/img/equation_sample_mean.svg new file mode 100644 index 000000000000..aea7a5f6687a --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/img/equation_sample_mean.svg @@ -0,0 +1,43 @@ + +x overbar 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/dvariancech/docs/repl.txt b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/repl.txt new file mode 100644 index 000000000000..b1cbee96616c --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/repl.txt @@ -0,0 +1,44 @@ + +{{alias}}( arrays ) + Computes the variance of a one-dimensional double-precision floating-point + ndarray using a one-pass trial mean algorithm. + + If provided an empty one-dimensional ndarray, the function returns `NaN`. + + If `N - c` is less than or equal to `0` (where `N` corresponds to the number + of elements in the input ndarray and `c` corresponds to the provided degrees + of freedom adjustment), the function returns `NaN`. + + Parameters + ---------- + arrays: ArrayLikeObject + Array-like object containing the following ndarrays: + + - a one-dimensional input ndarray. + - a zero-dimensional ndarray specifying the degrees of freedom + adjustment. Providing a non-zero degrees of freedom adjustment has the + effect of adjusting the divisor during the calculation of the variance + according to `N-c` where `N` is the number of elements in the input + ndarray and `c` corresponds to the provided degrees of freedom + adjustment. When computing the variance of a population, setting this + parameter to `0` is the standard choice (i.e., the provided array + contains data constituting an entire population). When computing the + corrected sample variance, setting this parameter to `1` is the standard + choice (i.e., the provided array contains data sampled from a larger + population; this is commonly referred to as Bessel's correction). + + Returns + ------- + out: number + The variance. + + Examples + -------- + > var x = new {{alias:@stdlib/ndarray/vector/float64}}( [ 1.0, -2.0, 2.0 ] ); + > var opts = { 'dtype': 'float64' }; + > var correction = {{alias:@stdlib/ndarray/from-scalar}}( 1.0, opts ); + > {{alias}}( [ x, correction ] ) + ~4.3333 + + See Also + -------- diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/index.d.ts b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/index.d.ts new file mode 100644 index 000000000000..f7bc8c83a456 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/index.d.ts @@ -0,0 +1,57 @@ +/* +* @license Apache-2.0 +* +* Copyright (c) 2026 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 { float64ndarray, typedndarray } from '@stdlib/types/ndarray'; + +/** +* Computes the variance of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean algorithm. +* +* ## Notes +* +* - The function expects the following ndarrays: +* +* - a one-dimensional input ndarray. +* - a zero-dimensional ndarray specifying the degrees of freedom adjustment. +* +* @param arrays - array-like object containing ndarrays +* @returns variance +* +* @example +* var Float64Vector = require( '@stdlib/ndarray/vector/float64' ); +* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +* +* var opts = { +* 'dtype': 'float64' +* }; +* +* var x = new Float64Vector( [ 1.0, -2.0, 2.0 ] ); +* var correction = scalar2ndarray( 1.0, opts ); +* +* var v = dvariancech( [ x, correction ] ); +* // returns ~4.3333 +*/ +declare function dvariancech( arrays: [ float64ndarray, typedndarray ] ): number; + + +// EXPORTS // + +export = dvariancech; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/test.ts b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/test.ts new file mode 100644 index 000000000000..e2695aa2807f --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/docs/types/test.ts @@ -0,0 +1,64 @@ +/* +* @license Apache-2.0 +* +* Copyright (c) 2026 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 scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +import dvariancech = require( './index' ); + + +// TESTS // + +// The function returns a number... +{ + const x = zeros( [ 10 ], { + 'dtype': 'float64' + }); + const correction = scalar2ndarray( 1.0, { + 'dtype': 'float64' + }); + + dvariancech( [ x, correction ] ); // $ExpectType number +} + +// The compiler throws an error if the function is provided a first argument which is not an array of ndarrays... +{ + dvariancech( '10' ); // $ExpectError + dvariancech( 10 ); // $ExpectError + dvariancech( true ); // $ExpectError + dvariancech( false ); // $ExpectError + dvariancech( null ); // $ExpectError + dvariancech( undefined ); // $ExpectError + dvariancech( [] ); // $ExpectError + dvariancech( {} ); // $ExpectError + dvariancech( ( 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': 'float64' + }); + const correction = scalar2ndarray( 1.0, { + 'dtype': 'float64' + }); + + dvariancech(); // $ExpectError + dvariancech( [ x, correction ], 10 ); // $ExpectError +} diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/examples/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/examples/index.js new file mode 100644 index 000000000000..0ac519a520dc --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/examples/index.js @@ -0,0 +1,35 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2026 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/discrete-uniform' ); +var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +var ndarray2array = require( '@stdlib/ndarray/to-array' ); +var dvariancech = require( './../lib' ); + +var opts = { + 'dtype': 'float64' +}; + +var x = discreteUniform( [ 10 ], -50, 50, opts ); +console.log( ndarray2array( x ) ); + +var correction = scalar2ndarray( 1.0, opts ); +var v = dvariancech( [ x, correction ] ); +console.log( v ); diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/index.js b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/index.js new file mode 100644 index 000000000000..ea78bc2abdcf --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/index.js @@ -0,0 +1,49 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2026 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 variance of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean algorithm. +* +* @module @stdlib/stats/base/ndarray/dvariancech +* +* @example +* var Float64Vector = require( '@stdlib/ndarray/vector/float64' ); +* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +* var dvariancech = require( '@stdlib/stats/base/ndarray/dvariancech' ); +* +* var opts = { +* 'dtype': 'float64' +* }; +* +* var x = new Float64Vector( [ 1.0, -2.0, 2.0 ] ); +* var correction = scalar2ndarray( 1.0, opts ); +* +* var v = dvariancech( [ x, correction ] ); +* // returns ~4.3333 +*/ + +// MODULES // + +var main = require( './main.js' ); + + +// EXPORTS // + +module.exports = main; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/main.js b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/main.js new file mode 100644 index 000000000000..3f228c6b1c09 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/lib/main.js @@ -0,0 +1,74 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2026 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 ndarraylike2scalar = require( '@stdlib/ndarray/base/ndarraylike2scalar' ); +var strided = require( '@stdlib/stats/strided/dvariancech' ).ndarray; + + +// MAIN // + +/** +* Computes the variance of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean algorithm. +* +* ## Notes +* +* - The function expects the following ndarrays: +* +* - a one-dimensional input ndarray. +* - a zero-dimensional ndarray specifying the degrees of freedom adjustment. +* +* @param {ArrayLikeObject} arrays - array-like object containing ndarrays +* @returns {number} variance +* +* @example +* var Float64Vector = require( '@stdlib/ndarray/vector/float64' ); +* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +* +* var opts = { +* 'dtype': 'float64' +* }; +* +* var x = new Float64Vector( [ 1.0, -2.0, 2.0 ] ); +* +* var correction = scalar2ndarray( 1.0, opts ); +* +* var v = dvariancech( [ x, correction ] ); +* // returns ~4.3333 +*/ +function dvariancech( arrays ) { + var correction; + var x; + + x = arrays[ 0 ]; + correction = ndarraylike2scalar( arrays[ 1 ] ); + + return strided( numelDimension( x, 0 ), correction, getData( x ), getStride( x, 0 ), getOffset( x ) ); // eslint-disable-line max-len +} + + +// EXPORTS // + +module.exports = dvariancech; diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/package.json b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/package.json new file mode 100644 index 000000000000..19a6c7f6fc46 --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/package.json @@ -0,0 +1,75 @@ +{ + "name": "@stdlib/stats/base/ndarray/dvariancech", + "version": "0.0.0", + "description": "Compute the variance of a one-dimensional double-precision floating-point ndarray using a one-pass trial mean 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", + "variance", + "var", + "deviation", + "dispersion", + "spread", + "sample variance", + "unbiased", + "dvariancech", + "std", + "ndarray", + "float64", + "double", + "double-precision", + "typed", + "float64array" + ], + "__stdlib__": {} +} diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/test/test.js b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/test/test.js new file mode 100644 index 000000000000..8b6834cdafde --- /dev/null +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/test/test.js @@ -0,0 +1,227 @@ +/** +* @license Apache-2.0 +* +* Copyright (c) 2026 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 Float64Array = require( '@stdlib/array/float64' ); +var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' ); +var ndarray = require( '@stdlib/ndarray/base/ctor' ); +var dvariancech = 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( 'float64', buffer, [ length ], [ stride ], offset, 'row-major' ); +} + + +// TESTS // + +tape( 'main export is a function', function test( t ) { + t.ok( true, __filename ); + t.strictEqual( typeof dvariancech, 'function', 'main export is a function' ); + t.end(); +}); + +tape( 'the function has an arity of 1', function test( t ) { + t.strictEqual( dvariancech.length, 1, 'has expected arity' ); + t.end(); +}); + +tape( 'the function calculates the variance of a one-dimensional ndarray', function test( t ) { + var correction; + var expected; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array( [ 1.0, -2.0, -4.0, 5.0, 0.0, 3.0 ] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, x.length, 1, 0 ), correction ] ); + expected = 53.5 / (x.length-1); + t.strictEqual( v, expected, 'returns expected value' ); + + x = new Float64Array( [ -4.0, -5.0 ] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, x.length, 1, 0 ), correction ] ); + expected = 0.5; + t.strictEqual( v, expected, 'returns expected value' ); + + x = new Float64Array( [ NaN ] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, x.length, 1, 0 ), correction ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + x = new Float64Array( [ NaN, NaN ] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, x.length, 1, 0 ), correction ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + t.end(); +}); + +tape( 'if provided an empty ndarray, the function returns `NaN`', function test( t ) { + var correction; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array( [] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, 0, 1, 0 ), correction ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + t.end(); +}); + +tape( 'if provided a correction argument yielding `N-correction` less than or equal to `0`, the function returns `NaN`', function test( t ) { + var correction; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array( [ 1.0 ] ); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, 1, 1, 0 ), correction ] ); + t.strictEqual( isnan( v ), true, 'returns expected value' ); + + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having non-unit strides', function test( t ) { + var correction; + var expected; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array([ + 1.0, // 0 + 2.0, + 2.0, // 1 + -7.0, + -2.0, // 2 + 3.0, + 4.0, // 3 + 2.0 + ]); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, 4, 2, 0 ), correction ] ); + expected = 6.25; + t.strictEqual( v, expected, 'returns expected value' ); + + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having negative strides', function test( t ) { + var correction; + var expected; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array([ + 1.0, // 3 + 2.0, + 2.0, // 2 + -7.0, + -2.0, // 1 + 3.0, + 4.0, // 0 + 2.0 + ]); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, 4, -2, 6 ), correction ] ); + expected = 6.25; + t.strictEqual( v, expected, 'returns expected value' ); + + t.end(); +}); + +tape( 'the function supports one-dimensional ndarrays having non-zero offsets', function test( t ) { + var correction; + var expected; + var opts; + var x; + var v; + + opts = { + 'dtype': 'float64' + }; + + x = new Float64Array([ + 2.0, + 1.0, // 0 + 2.0, + -2.0, // 1 + -2.0, + 2.0, // 2 + 3.0, + 4.0 // 3 + ]); + correction = scalar2ndarray( 1.0, opts ); + + v = dvariancech( [ vector( x, 4, 2, 1 ), correction ] ); + expected = 6.25; + t.strictEqual( v, expected, 'returns expected value' ); + + t.end(); +}); From 65a001abfac266a0b9d9eaaecac4d4d1f0b787ea Mon Sep 17 00:00:00 2001 From: Athan Date: Fri, 14 Aug 2026 19:51:08 -0700 Subject: [PATCH 2/2] Apply suggestions from code review Co-authored-by: Athan Signed-off-by: Athan --- .../@stdlib/stats/base/ndarray/dvariancech/README.md | 2 -- 1 file changed, 2 deletions(-) diff --git a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md index 7326c37513b4..a007dafc016e 100644 --- a/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md +++ b/lib/node_modules/@stdlib/stats/base/ndarray/dvariancech/README.md @@ -186,8 +186,6 @@ console.log( v );
-* * * -