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feat: add blas/base/scasum
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PR-URL: #2573
Ref: #2039
Co-authored-by: Athan Reines <kgryte@gmail.com>
Reviewed-by: Athan Reines <kgryte@gmail.com>
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267 changes: 267 additions & 0 deletions lib/node_modules/@stdlib/blas/base/scasum/README.md
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<!--
@license Apache-2.0
Copyright (c) 2024 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.
-->

# scasum

> Compute the sum of the absolute values of the real and imaginary components of a single-precision complex floating-point vector.
<section class="usage">

## Usage

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

#### scasum( N, cx, strideX )

Computes the sum of the absolute values of the real and imaginary components of a single-precision complex floating-point vector.

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

var cx = new Complex64Array( [ 0.3, 0.1, 0.5, 0.0, 0.0, 0.5, 0.0, 0.2 ] );

var out = scasum( 4, cx, 1 );
// returns ~1.6
```

The function has the following parameters:

- **N**: number of indexed elements.
- **cx**: input [`Complex64Array`][@stdlib/array/complex64].
- **strideX**: index increment for `cx`.

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

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

var cx = new Complex64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

var out = scasum( 2, cx, 2 );
// returns 7.0
```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.

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

// Initial array:
var cx0 = new Complex64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

// Create an offset view:
var cx1 = new Complex64Array( cx0.buffer, cx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Compute the L2-out:
var out = scasum( 2, cx1, 1 );
// returns 18.0
```

#### scasum.ndarray( N, cx, strideX, offset )

Computes the sum of the absolute values of the real and imaginary components of a single-precision complex floating-point vector using alternative indexing semantics.

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

var cx = new Complex64Array( [ 0.3, 0.1, 0.5, 0.0, 0.0, 0.5, 0.0, 0.2 ] );

var out = scasum.ndarray( 4, cx, 1, 0 );
// returns ~1.6
```

The function has the following additional parameters:

- **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 start from the second index,

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

var cx = new Complex64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

var out = scasum.ndarray( 2, cx, 1, 1 );
// returns 18.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

- If `N <= 0`, both functions return `0.0`.
- `scasum()` corresponds to the [BLAS][blas] level 1 function [`scasum`][scasum].

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
var filledarrayBy = require( '@stdlib/array/filled-by' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );
var scasum = require( '@stdlib/blas/base/scasum' );

function rand() {
return new Complex64( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}

var cx = filledarrayBy( 10, 'complex64', rand );
console.log( cx.toString() );

// Compute the sum of the absolute values of real and imaginary components:
var out = scasum( cx.length, cx, 1 );
console.log( out );
```

</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/base/scasum.h"
```

#### c_scasum( N, \*CX, strideX )

Computes the sum of the absolute values of the real and imaginary components of a single-precision complex floating-point vector.

```c
const float cx[] = { 0.3f, 0.1f, 0.5f, 0.0f, 0.0f, 0.5f, 0.0f, 0.2f };

float out = c_scasum( 4, (void *)cx, 1 );
// returns 1.6f
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **CX**: `[in] void*` input array.
- **strideX**: `[in] CBLAS_INT` index increment for `CX`.
```c
float c_scasum( const CBLAS_INT N, const void *CX, const CBLAS_INT strideX );
```

</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/blas/base/scasum.h"
#include <stdio.h>

int main( void ) {
// Create a strided array of interleaved real and imaginary components:
const float cx[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };

// Specify the number of elements:
const int N = 4;

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

// Compute the sum of the absolute values of real and imaginary components:
float out = c_scasum( N, (void *)cx, strideX );

// Print the result:
printf( "out: %f\n", out );
}
```
</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">
[blas]: http://www.netlib.org/blas
[scasum]: https://www.netlib.org/lapack/explore-html/d5/d72/group__asum_ga89c76eef329f84ba9ed106b34fedab16.html#ga89c76eef329f84ba9ed106b34fedab16
[@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
</section>
<!-- /.links -->
92 changes: 92 additions & 0 deletions lib/node_modules/@stdlib/blas/base/scasum/benchmark/benchmark.js
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/**
* @license Apache-2.0
*
* Copyright (c) 2024 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/array/uniform' );
var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
var pow = require( '@stdlib/math/base/special/pow' );
var Complex64Array = require( '@stdlib/array/complex64' );
var pkg = require( './../package.json' ).name;
var scasum = require( './../lib/scasum.js' );


// VARIABLES //

var options = {
'dtype': 'float32'
};


// FUNCTIONS //

/**
* Create a benchmark function.
*
* @private
* @param {PositiveInteger} len - array length
* @returns {Function} benchmark function
*/
function createBenchmark( len ) {
var cx = new Complex64Array( uniform( len*2, -10.0, 10.0, options ) );
return benchmark;

function benchmark( b ) {
var out;
var i;

b.tic();
for ( i = 0; i < b.iterations; i++ ) {
out = scasum( cx.length, cx, 1 );
if ( isnanf( out ) ) {
b.fail( 'should not return NaN' );
}
}
b.toc();
if ( isnanf( out ) ) {
b.fail( 'should not return NaN' );
}
b.pass( 'benchmark finished' );
b.end();
}
}


// MAIN //

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( pkg+':len='+len, f );
}
}

main();
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Coverage Report

Package Statements Branches Functions Lines
blas/base/scasum $\color{green}369/369$
$\color{green}+100.00\%$
$\color{green}18/18$
$\color{green}+100.00\%$
$\color{green}4/4$
$\color{green}+100.00\%$
$\color{green}369/369$
$\color{green}+100.00\%$

The above coverage report was generated for the changes in this push.

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