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331 changes: 331 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/cnancount/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.

-->

# cnancount

> Calculate the number of non-`NaN` elements in a single-precision complex floating-point strided array.

<section class="intro">

</section>

<!-- /.intro -->

<section class="usage">

## Usage

```javascript
var cnancount = require( '@stdlib/blas/ext/base/cnancount' );
```

#### cnancount( N, x, strideX )

Computes the number of non-`NaN` elements in a single-precision complex floating-point strided array.

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );

var x = new Complex64Array( [ 1.0, -2.0, NaN, 2.0 ] );

var v = cnancount( x.length, x, 1 );
// returns 1
```

The function has the following parameters:

- **N**: number of indexed elements.
- **x**: input [`Complex64Array`][@stdlib/array/complex64].
- **strideX**: stride length.

The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to count every other element in `x`,

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );

var x = new Complex64Array( [ 1.0, 2.0, NaN, -2.0, 4.0, 3.0, NaN, NaN ] );

var v = cnancount( 2, x, 2 );
// returns 2
```

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 Complex64Array = require( '@stdlib/array/complex64' );

var x0 = new Complex64Array( [ 2.0, 1.0, NaN, -2.0, 3.0, 4.0, NaN, NaN ] );
var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var v = cnancount( 2, x1, 2 );
// returns 0
```

#### cnancount.ndarray( N, x, strideX, offsetX )

Computes the number of non-`NaN` elements in a single-precision complex floating-point strided array using alternative indexing semantics.

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );

var x = new Complex64Array( [ 2.0, 1.0, -2.0, -2.0, 3.0, 4.0, NaN, NaN ] );

var v = cnancount.ndarray( 4, x, 1, 0 );
// returns 3
```

The function has the following additional parameter:

- **offsetX**: starting index.

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 count every other element in `x` starting from the second element,

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );

var x = new Complex64Array( [ 2.0, 1.0, NaN, -2.0, 3.0, 4.0, NaN, NaN ] );

var v = cnancount.ndarray( 2, x, 2, 1 );
// returns 0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

- If `N <= 0`, both functions return `0`.
- An element is considered `NaN` if either its real or imaginary component is `NaN`.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var uniform = require( '@stdlib/random/base/uniform' );
var filledarrayBy = require( '@stdlib/array/filled-by' );
var bernoulli = require( '@stdlib/random/base/bernoulli' );
var Complex64Array = require( '@stdlib/array/complex64' );
var cnancount = require( '@stdlib/blas/ext/base/cnancount' );

function rand() {
if ( bernoulli( 0.8 ) < 1 ) {
return NaN;
}
return uniform( -50.0, 50.0 );
}

var xbuf = filledarrayBy( 10, 'float32', rand );
console.log( xbuf );

var x = new Complex64Array( xbuf );
var v = cnancount( 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/blas/ext/base/cnancount.h"
```

#### stdlib_strided_cnancount( N, \*X, strideX )

Computes the number of non-`NaN` elements in a single-precision complex floating-point strided array.

```c
#include "stdlib/complex/float32/ctor.h"

const stdlib_complex64_t x[] = {
stdlib_complex64( 1.0f, 2.0f ),
stdlib_complex64( 3.0f, 4.0f ),
stdlib_complex64( 0.0f/0.0f, -2.0f ),
stdlib_complex64( 5.0f, 6.0f ),
stdlib_complex64( 7.0f, 8.0f ),
stdlib_complex64( 9.0f, 10.0f ),
stdlib_complex64( 0.0f/0.0f, 0.0f/0.0f ),
stdlib_complex64( 11.0f, 12.0f )
};

int v = stdlib_strided_cnancount( 4, x, 2 );
// returns 2
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] stdlib_complex64_t*` input array.
- **strideX**: `[in] CBLAS_INT` stride length.

```c
CBLAS_INT stdlib_strided_cnancount( const CBLAS_INT N, const stdlib_complex64_t *X, const CBLAS_INT strideX );
```

#### stdlib_strided_cnancount_ndarray( N, \*X, strideX, offsetX )

Computes the number of non-`NaN` elements in a single-precision complex floating-point strided array using alternative indexing semantics.

```c
#include "stdlib/complex/float32/ctor.h"

const stdlib_complex64_t x[] = {
stdlib_complex64( 2.0f, 1.0f ),
stdlib_complex64( -2.0f, -3.0f ),
stdlib_complex64( 0.0f/0.0f, -2.0f ),
stdlib_complex64( 3.0f, 4.0f ),
stdlib_complex64( 5.0f, 6.0f ),
stdlib_complex64( 0.0f/0.0f, 0.0f/0.0f ),
stdlib_complex64( 7.0f, 8.0f ),
stdlib_complex64( 9.0f, 10.0f )
};

int v = stdlib_strided_cnancount_ndarray( 4, x, 2, 1 );
// returns 3
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] stdlib_complex64_t*` input array.
- **strideX**: `[in] CBLAS_INT` stride length.
- **offsetX**: `[in] CBLAS_INT` starting index.

```c
CBLAS_INT stdlib_strided_cnancount_ndarray( const CBLAS_INT N, const stdlib_complex64_t *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">

### Notes

- If `N <= 0`, both functions return `0`.
- An element is considered `NaN` if either its real or imaginary component is `NaN`.

</section>

<!-- /.notes -->

<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#include "stdlib/blas/ext/base/cnancount.h"
#include "stdlib/complex/float32/ctor.h"
#include <stdio.h>

int main( void ) {
// Create a strided array:
const stdlib_complex64_t x[] = {
stdlib_complex64( 1.0f, 2.0f ),
stdlib_complex64( 3.0f, 4.0f ),
stdlib_complex64( 0.0f/0.0f, 5.0f ), // NaN
stdlib_complex64( 6.0f, 0.0f/0.0f ), // NaN
stdlib_complex64( 7.0f, 8.0f )
};

// Specify the number of indexed elements:
const int N = 5;

// Specify the stride length:
const int strideX = 1;

// Compute the number of non-NaN elements:
int v = stdlib_strided_cnancount( N, x, strideX );

// Print the result:
printf( "count: %d\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">

[@stdlib/array/complex64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/complex64

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

<!-- <related-links> -->

<!-- </related-links> -->

</section>

<!-- /.links -->
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