feat: add stats/strided/dnanmidrange

lib/node_modules/@stdlib/stats/strided/dnanmidrange/README.md

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+<!--
+
+@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.
+
+-->
+
+# dnanmidrange
+
+> Calculate the [mid-range][mid-range] of a double-precision floating-point strided array, ignoring `NaN` values.
+
+<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 dnanmidrange = require( '@stdlib/stats/strided/dnanmidrange' );
+```
+
+#### dnanmidrange( N, x, strideX )
+
+Computes the [mid-range][mid-range] of a double-precision floating-point strided array `x`, ignoring `NaN` values.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
+
+var v = dnanmidrange( x.length, x, 1 );
+// returns 0.0
+```
+
+The function has the following parameters:
+
+-   **N**: number of indexed elements.
+-   **x**: input [`Float64Array`][@stdlib/array/float64].
+-   **strideX**: index increment for `x`.
+
+The `N` and `stride` parameters determine which elements in the strided array are accessed at runtime. For example, to compute the [mid-range][mid-range] of every other element in `x`,
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var x = new Float64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0, NaN ] );
+
+var v = dnanmidrange( 5, x, 2 );
+// returns 1.0
+```
+
+Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
+
+<!-- eslint-disable stdlib/capitalized-comments -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var x0 = new Float64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, NaN, NaN ] );
+var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+var v = dnanmidrange( 4, x1, 2 );
+// returns 1.0
+```
+
+#### dnanmidrange.ndarray( N, x, strideX, offsetX )
+
+Computes the [mid-range][mid-range] of a double-precision floating-point strided array, ignoring `NaN` values and using alternative indexing semantics.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );
+
+var v = dnanmidrange.ndarray( x.length, x, 1, 0 );
+// returns 0.0
+```
+
+The function has the following additional parameters:
+
+-   **offsetX**: starting index for `x`.
+
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to calculate the [mid-range][mid-range] for every other element in `x` starting from the second element
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var x = new Float64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, NaN, NaN ] );
+
+var v = dnanmidrange.ndarray( 4, x, 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 randu = require( '@stdlib/random/base/randu' );
+var round = require( '@stdlib/math/base/special/round' );
+var Float64Array = require( '@stdlib/array/float64' );
+var dnanmidrange = require( '@stdlib/stats/strided/dnanmidrange' );
+
+var x;
+var i;
+
+x = new Float64Array( 10 );
+for ( i = 0; i < x.length; i++ ) {
+    if ( randu() < 0.2 ) {
+        x[ i ] = NaN;
+    } else {
+        x[ i ] = round( (randu()*100.0) - 50.0 );
+    }
+}
+console.log( x );
+
+var v = dnanmidrange( x.length, x, 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/dnanmidrange.h"
+```
+
+#### stdlib_strided_dnanmidrange( N, \*X, strideX )
+
+Computes the [mid-range][mid-range] of a double-precision floating-point strided array `x`, ignoring `NaN` values.
+
+```c
+const double x[] = { 1.0, 0.0/0.0, 3.0, -4.0 };
+
+double v = stdlib_strided_dnanmidrange( 4, x, 1 );
+// returns -0.5
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] double*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+
+```c
+double stdlib_strided_dnanmidrange( const CBLAS_INT N, const double *X, const CBLAS_INT strideX );
+```
+
+#### stdlib_strided_dnanmidrange_ndarray( N, \*X, strideX, offsetX )
+
+Computes the [mid-range][mid-range] of a double-precision floating-point strided array, ignoring `NaN` values and using alternative indexing semantics.
+
+```c
+const double x[] = { 1.0, 0.0/0.0, 3.0, -4.0 };
+
+double v = stdlib_strided_dnanmidrange_ndarray( 4, x, 1, 0 );
+// returns -0.5
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] double*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+-   **offsetX**: `[in] CBLAS_INT` starting index for `X`.
+
+```c
+double stdlib_strided_dnanmidrange_ndarray( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );
+```
+
+</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/dnanmidrange.h"
+#include <stdio.h>
+
+int main( void ) {
+    // Create a strided array:
+    const double x[] = { 1.0, -2.0, -3.0, 4.0, -5.0, -6.0, 7.0, 8.0, 0.0/0.0, 0.0/0.0 };
+
+    // Specify the number of elements:
+    const int N = 5;
+
+    // Specify the stride length:
+    const int strideX = 2;
+
+    // Compute the mid-range:
+    double v = stdlib_strided_dnanmidrange( N, x, strideX );
+
+    // Print the result:
+    printf( "mid-range: %lf\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">
+
+* * *
+
+## See Also
+
+-   <span class="package-name">[`@stdlib/stats/strided/dmidrange`][@stdlib/stats/strided/dmidrange]</span><span class="delimiter">: </span><span class="description">calculate the mid-range of a double-precision floating-point strided array.</span>
+-   <span class="package-name">[`@stdlib/stats/strided/dnanmax`][@stdlib/stats/strided/dnanmax]</span><span class="delimiter">: </span><span class="description">calculate the maximum value of a double-precision floating-point strided array, ignoring NaN values.</span>
+-   <span class="package-name">[`@stdlib/stats/strided/dnanmin`][@stdlib/stats/strided/dnanmin]</span><span class="delimiter">: </span><span class="description">calculate the minimum value of a double-precision floating-point strided array, ignoring NaN values.</span>
+-   <span class="package-name">[`@stdlib/stats/strided/nanmidrange`][@stdlib/stats/strided/nanmidrange]</span><span class="delimiter">: </span><span class="description">calculate the mid-range of a strided array, ignoring NaN values.</span>
+-   <span class="package-name">[`@stdlib/stats/strided/snanmidrange`][@stdlib/stats/strided/snanmidrange]</span><span class="delimiter">: </span><span class="description">calculate the mid-range of a single-precision floating-point strided array, ignoring NaN values.</span>
+
+</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/float64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/float64
+
+[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
+
+<!-- <related-links> -->
+
+[@stdlib/stats/strided/dmidrange]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/strided/dmidrange
+
+[@stdlib/stats/strided/dnanmax]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/strided/dnanmax
+
+[@stdlib/stats/strided/dnanmin]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/strided/dnanmin
+
+[@stdlib/stats/strided/nanmidrange]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/strided/nanmidrange
+
+[@stdlib/stats/strided/snanmidrange]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/strided/snanmidrange
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->