feat: add stats/incr/nanrss

lib/node_modules/@stdlib/stats/incr/nanrss/README.md

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+<!--
+
+@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.
+
+-->
+
+# incrnanrss
+
+> Compute the [residual sum of squares][residual-sum-of-squares] (RSS) incrementally, ignoring `NaN` values.
+
+<section class="intro">
+
+The [**residual sum of squares**][residual-sum-of-squares] (also referred to as the **sum of squared residuals** (SSR) and the **sum of squared errors** (SSE)) is defined as
+
+<!-- <equation class="equation" label="eq:residual_sum_of_squares" align="center" raw="\operatorname{RSS} = \sum_{i=0}^{n-1} (y_i - x_i)^2" alt="Equation for the residual sum of squares."> -->
+
+```math
+\mathop{\mathrm{RSS}} = \sum_{i=0}^{n-1} (y_i - x_i)^2
+```
+
+<!-- <div class="equation" align="center" data-raw-text="\operatorname{RSS} = \sum_{i=0}^{n-1} (y_i - x_i)^2" data-equation="eq:residual_sum_of_squares">
+    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@78799028a150a44d463029bdb62ac870b1c1f9d4/lib/node_modules/@stdlib/stats/incr/rss/docs/img/equation_residual_sum_of_squares.svg" alt="Equation for the residual sum of squares.">
+    <br>
+</div> -->
+
+<!-- </equation> -->
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var incrnanrss = require( '@stdlib/stats/incr/nanrss' );
+```
+
+#### incrnanrss()
+
+Returns an accumulator `function` which incrementally computes the [residual sum of squares][residual-sum-of-squares], ignoring NaN values.
+
+```javascript
+var accumulator = incrnanrss();
+```
+
+#### accumulator( \[x, y] )
+
+If provided input values x and y, the accumulator function updates the RSS. If NaN is provided, it is ignored, and the previous RSS is returned. If no arguments are provided, the accumulator function returns the current RSS.
+
+```javascript
+var accumulator = incrnanrss();
+
+var r = accumulator( 2.0, 3.0 );
+// returns 1.0
+
+r = accumulator( -1.0, -4.0 );
+// returns 10.0
+
+r = accumulator( -3.0, 5.0 );
+// returns 74.0
+
+r = accumulator( NaN, 3.0 );
+// returns 74.0
+
+r = accumulator();
+// returns 74.0
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   Input values are **not** type checked. If provided `NaN` or a value which, when used in computations, results in `NaN`, the accumulated value is `NaN` for **all** future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var incrnanrss = require( '@stdlib/stats/incr/nanrss' );
+
+var accumulator;
+var v1;
+var v2;
+var i;
+
+// Initialize an accumulator:
+accumulator = incrnanrss();
+
+// For each simulated datum, update the residual sum of squares...
+for ( i = 0; i < 100; i++ ) {
+    v1 = ( randu()*100.0 ) - 50.0;
+    v2 = ( randu()*100.0 ) - 50.0;
+    accumulator( v1, v2 );
+
+    // NaN values are ignored
+    accumulator( NaN, v2 );
+}
+console.log( accumulator() );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[residual-sum-of-squares]: https://en.wikipedia.org/wiki/Residual_sum_of_squares
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->
+

lib/node_modules/@stdlib/stats/incr/nanrss/benchmark/benchmark.js

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+/**
+* @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 randu = require( '@stdlib/random/base/randu' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var incrnanrss = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var f;
+	var i;
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		f = incrnanrss();
+		if ( typeof f !== 'function' ) {
+			b.fail( 'should return a function' );
+		}
+	}
+	b.toc();
+	if ( typeof f !== 'function' ) {
+		b.fail( 'should return a function' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( format( '%s::accumulator', pkg ), function benchmark( b ) {
+	var acc;
+	var v;
+	var i;
+
+	acc = incrnanrss();
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		if ( i % 10 === 0 ) {
+			v = acc( NaN, randu() -0.5 );
+		} else {
+			v = acc( randu() -0.5, randu() -0.5 );
+		}
+		if ( v !== v ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( v !== v ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/stats/incr/nanrss/docs/repl.txt

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+{{alias}}()
+    Returns an accumulator function which incrementally computes the residual
+    sum of squares (RSS), ignoring `NaN` values.
+
+    If provided input values, the accumulator function returns an updated
+    residual sum of squares. If not provided input values, the accumulator
+    function returns the current residual sum of squares.
+
+    NaN input values are ignored.
+
+    Returns
+    -------
+    acc: Function
+        Accumulator function.
+
+    Examples
+    --------
+    > var accumulator = {{alias}}();
+    > var r = accumulator()
+    null
+    > r = accumulator( 2.0, 3.0 )
+    1.0
+    > r = accumulator( NaN, 3.0 )
+    1.0
+    > r = accumulator( -5.0, 2.0 )
+    50.0
+    > r = accumulator()
+    50.0
+
+    See Also
+    --------

lib/node_modules/@stdlib/stats/incr/nanrss/docs/types/index.d.ts

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+/*
+* @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
+
+/// <reference types="@stdlib/types"/>
+
+/**
+* If provided arguments, returns an updated residual sum of squares; otherwise, returns the current residual sum of squares.
+*
+* ## Notes
+*
+*  NaN input values are ignored.
+* @returns residual sum of squares
+*/
+type accumulator = ( x?: number, y?: number ) => number | null;
+
+/**
+* Returns an accumulator function which incrementally computes the residual sum of squares, ignoring `NaN` values.
+*
+* @returns accumulator function
+*
+* @example
+* var accumulator = incrnanrss();
+*
+* var r = accumulator();
+* // returns null
+*
+* r = accumulator( 2.0, 3.0 );
+* // returns 1.0
+*
+* r = accumulator( -5.0, 2.0 );
+* // returns 50.0
+*
+* r = accumulator();
+* // returns 50.0
+* r = accumulator( NaN, 3.0 );
+* // 50.0
+* r = accumulator( 5.0, NaN );
+* // 50.0
+*/
+declare function incrnanrss(): accumulator;
+
+
+// EXPORTS //
+
+export = incrnanrss;
+