feat: add stats/strided/smskmidrange

lib/node_modules/@stdlib/stats/strided/smskmidrange/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.
+
+-->
+
+# smskmidrange
+
+> Calculate the [mid-range][mid-range] of a single-precision floating-point strided array according to a mask.
+
+<section class="intro">
+
+The [**mid-range**][mid-range], or **mid-extreme**, is the arithmetic mean of the maximum and minimum values in a data set. The measure is the midpoint of the range and a measure of central tendency.
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var smskmidrange = require( '@stdlib/stats/strided/smskmidrange' );
+```
+
+#### smskmidrange( N, x, strideX, mask, strideMask )
+
+Computes the [mid-range][mid-range] of a single-precision floating-point strided array according to a mask.
+
+```javascript
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+
+var x = new Float32Array( [ 1.0, -2.0, 4.0, 2.0 ] );
+var mask = new Uint8Array( [ 0, 0, 1, 0 ] );
+
+var v = smskmidrange( x.length, x, 1, mask, 1 );
+// returns 0.0
+```
+
+The function has the following parameters:
+
+-   **N**: number of indexed elements.
+-   **x**: input [`Float32Array`][@stdlib/array/float32].
+-   **strideX**: stride length for `x`.
+-   **mask**: mask [`Uint8Array`][@stdlib/array/uint8]. If a `mask` array element is `0`, the corresponding element in `x` is considered valid and **included** in computation. If a `mask` array element is `1`, the corresponding element in `x` is considered invalid/missing and **excluded** from computation.
+-   **strideMask**: stride length for `mask`.
+
+The `N` and stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to compute the [mid-range][mid-range] of every other element in `x`,
+
+```javascript
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+
+var x = new Float32Array( [ 1.0, 2.0, -7.0, -2.0, 4.0, 3.0, 5.0, 6.0 ] );
+var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
+
+var v = smskmidrange( 4, x, 2, mask, 2 );
+// returns -1.5
+```
+
+Note that indexing is relative to the first index. To introduce offsets, use [`typed array`][mdn-typed-array] views.
+
+<!-- eslint-disable stdlib/capitalized-comments -->
+
+```javascript
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+
+var x0 = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+var mask0 = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
+var mask1 = new Uint8Array( mask0.buffer, mask0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+var v = smskmidrange( 4, x1, 2, mask1, 2 );
+// returns 1.0
+```
+
+#### smskmidrange.ndarray( N, x, strideX, offsetX, mask, strideMask, offsetMask )
+
+Computes the [mid-range][mid-range] of a single-precision floating-point strided array according to a `mask` and using alternative indexing semantics.
+
+```javascript
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+
+var x = new Float32Array( [ 1.0, -2.0, 4.0, 2.0 ] );
+var mask = new Uint8Array( [ 0, 0, 1, 0 ] );
+
+var v = smskmidrange.ndarray( x.length, x, 1, 0, mask, 1, 0 );
+// returns 0.0
+```
+
+The function has the following additional parameters:
+
+-   **offsetX**: starting index for `x`.
+-   **offsetMask**: starting index for `mask`.
+
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to calculate the [mid-range][mid-range] for every other element in `x` starting from the second element
+
+```javascript
+var Float32Array = require( '@stdlib/array/float32' );
+var Uint8Array = require( '@stdlib/array/uint8' );
+
+var x = new Float32Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var mask = new Uint8Array( [ 0, 0, 0, 0, 0, 0, 1, 1 ] );
+
+var v = smskmidrange.ndarray( 4, x, 2, 1, mask, 2, 1 );
+// returns 1.0
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   If `N <= 0`, both functions return `NaN`.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var uniform = require( '@stdlib/random/array/uniform' );
+var bernoulli = require( '@stdlib/random/array/bernoulli' );
+var smskmidrange = require( '@stdlib/stats/strided/smskmidrange' );
+
+var x = uniform( 10, -50.0, 50.0, {
+    'dtype': 'float32'
+});
+console.log( x );
+
+var mask = bernoulli( x.length, 0.2, {
+    'dtype': 'uint8'
+});
+console.log( mask );
+
+var v = smskmidrange( x.length, x, 1, mask, 1 );
+console.log( v );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/stats/strided/smskmidrange.h"
+```
+
+#### stdlib_strided_smskmidrange( N, \*X, strideX, \*Mask, strideMask )
+
+Computes the [mid-range][mid-range] of a single-precision floating-point strided array according to a mask.
+
+```c
+#include <stdint.h>
+
+const float x[] = { 1.0f, -2.0f, 2.0f };
+const uint8_t mask[] = { 0, 1, 0 };
+
+float v = stdlib_strided_smskmidrange( 3, x, 1, mask, 1 );
+// returns 1.5f
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] float*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+-   **Mask**: `[in] uint8_t*` mask array. If a `Mask` array element is `0`, the corresponding element in `X` is considered valid and included in computation. If a `Mask` array element is `1`, the corresponding element in `X` is considered invalid/missing and excluded from computation.
+-   **strideMask**: `[in] CBLAS_INT` stride length for `Mask`.
+
+```c
+float stdlib_strided_smskmidrange( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const uint8_t *Mask, const CBLAS_INT strideMask );
+```
+
+<!-- lint disable maximum-heading-length -->
+
+#### stdlib_strided_smskmidrange_ndarray( N, \*X, strideX, offsetX, \*Mask, strideMask, offsetMask )
+
+Computes the [mid-range][mid-range] of a single-precision floating-point strided array according to a mask and using alternative indexing semantics.
+
+```c
+#include <stdint.h>
+
+const float x[] = { 1.0f, -2.0f, 2.0f };
+const uint8_t mask[] = { 0, 1, 0 };
+
+float v = stdlib_strided_smskmidrange_ndarray( 3, x, 1, 0, mask, 1, 0 );
+// returns 1.5f
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] float*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+-   **offsetX**: `[in] CBLAS_INT` starting index for `X`.
+-   **Mask**: `[in] uint8_t*` mask array. If a `Mask` array element is `0`, the corresponding element in `X` is considered valid and included in computation. If a `Mask` array element is `1`, the corresponding element in `X` is considered invalid/missing and excluded from computation.
+-   **strideMask**: `[in] CBLAS_INT` stride length for `Mask`.
+-   **offsetMask**: `[in] CBLAS_INT` starting index for `Mask`.
+
+```c
+float stdlib_strided_smskmidrange_ndarray( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const uint8_t *Mask, const CBLAS_INT strideMask, const CBLAS_INT offsetMask );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/stats/strided/smskmidrange.h"
+#include <stdint.h>
+#include <stdio.h>
+
+int main( void ) {
+    // Create a strided array:
+    const float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f };
+
+    // Create a mask array:
+    const uint8_t mask[] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 };
+
+    // Specify the number of elements:
+    const int N = 5;
+
+    // Specify the stride lengths:
+    const int strideX = 2;
+    const int strideMask = 2;
+
+    // Compute the mid-range:
+    float v = stdlib_strided_smskmidrange( N, x, strideX, mask, strideMask );
+
+    // Print the result:
+    printf( "mid-range: %f\n", v );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- 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">
+
+[mid-range]: https://en.wikipedia.org/wiki/Mid-range
+
+[@stdlib/array/float32]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/float32
+
+[@stdlib/array/uint8]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/uint8
+
+[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
+
+</section>
+
+<!-- /.links -->