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feat: add blas/base/zdrot
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PR-URL: #2257
Ref: #2039
Co-authored-by: Athan Reines <kgryte@gmail.com>
Reviewed-by: Athan Reines <kgryte@gmail.com> 
Signed-off-by: Aman Bhansali <92033532+aman-095@users.noreply.github.com>
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390 changes: 390 additions & 0 deletions lib/node_modules/@stdlib/blas/base/zdrot/README.md
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# zdrot

> Applies a plane rotation.
<section class="usage">

## Usage

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

#### zdrot( N, zx, strideX, zy, strideY, c, s )

Applies a plane rotation.

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

zdrot( zx.length, zx, 1, zy, 1, 0.8, 0.6 );

var z = zy.get( 0 );
// returns <Complex128>

var re = real( z );
// returns ~-0.6

var im = imag( z );
// returns ~-1.2

z = zx.get( 0 );
// returns <Complex128>

re = real( z );
// returns ~0.8

im = imag( z );
// returns ~1.6
```

The function has the following parameters:

- **N**: number of indexed elements.
- **zx**: first input [`Complex128Array`][@stdlib/array/complex128].
- **strideX**: index increment for `zx`.
- **zy**: second input [`Complex128Array`][@stdlib/array/complex128].
- **strideY**: index increment for `zy`.

The `N` and stride parameters determine how values from `zx` and `zy` are accessed at runtime. For example, to apply a plane rotation to every other element,

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

zdrot( 2, zx, 2, zy, 2, 0.8, 0.6 );

var z = zy.get( 0 );
// returns <Complex128>

var re = real( z );
// returns ~-0.6

var im = imag( z );
// returns ~-1.2

z = zx.get( 0 );
// returns <Complex128>

re = real( z );
// returns ~0.8

im = imag( z );
// returns ~1.6
```

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 Complex128Array = require( '@stdlib/array/complex128' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );

// Initial arrays...
var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy0 = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var zy1 = new Complex128Array( zy0.buffer, zy0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

zdrot( 2, zx1, -2, zy1, 1, 0.8, 0.6 );

var z = zy0.get( 2 );
// returns <Complex128>

var re = real( z );
// returns ~-4.2

var im = imag( z );
// returns ~-4.8

z = zx0.get( 3 );
// returns <Complex128>

re = real( z );
// returns ~5.6

im = imag( z );
// returns ~6.4
```

#### zdrot.ndarray( N, zx, strideX, offsetX, zy, strideY, offsetY, c, s )

Applies a plane rotation using alternative indexing semantics.

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

zdrot.ndarray( zx.length, zx, 1, 0, zy, 1, 0, 0.8, 0.6 );

var z = zy.get( 0 );
// returns <Complex128>

var re = real( z );
// returns ~-0.6

var im = imag( z );
// returns ~-1.2

z = zx.get( 0 );
// returns <Complex128>

re = real( z );
// returns ~0.8

im = imag( z );
// returns ~1.6
```

The function has the following additional parameters:

- **offsetX**: starting index for `zx`.
- **offsetY**: starting index for `zy`.

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 apply a plane rotation to every other element starting from the second element,

```javascript
var Complex128Array = require( '@stdlib/array/complex128' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );

var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var zy = new Complex128Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

zdrot.ndarray( 2, zx, 2, 1, zy, 2, 1, 0.8, 0.6 );

var z = zy.get( 3 );
// returns <Complex128>

var re = real( z );
// returns ~-4.2

var im = imag( z );
// returns ~-4.8

z = zx.get( 1 );
// returns <Complex128>

re = real( z );
// returns ~2.4

im = imag( z );
// returns ~3.2
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

- If `N <= 0`, both functions leave `zx` and `zy` unchanged.
- `zdrot()` corresponds to the [BLAS][blas] level 1 function [`zdrot`][zdrot].

</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 Complex128 = require( '@stdlib/complex/float64' );
var zcopy = require( '@stdlib/blas/base/zcopy' );
var zeros = require( '@stdlib/array/zeros' );
var logEach = require( '@stdlib/console/log-each' );
var zdrot = require( '@stdlib/blas/base/zdrot' );

function rand() {
return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
}

// Generate random input arrays:
var zx = filledarrayBy( 10, 'complex128', rand );
var zxc = zcopy( zx.length, zx, 1, zeros( zx.length, 'complex128' ), 1 );

var zy = filledarrayBy( 10, 'complex128', rand );
var zyc = zcopy( zy.length, zy, 1, zeros( zy.length, 'complex128' ), 1 );

// Apply a plane rotation:
zdrot( zx.length, zx, 1, zy, 1, 0.8, 0.6 );

// Print the results:
logEach( '(%s,%s) => (%s,%s)', zxc, zyc, zx, zy );
```

</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/zdrot.h"
```

#### c_zdrot( N, \*X, strideX, \*Y, strideY, c, s )

Applies a plane rotation.

```c
double x[] = { 1.0, 2.0, 3.0, 4.0 }; // interleaved real and imaginary components
double y[] = { 5.0, 6.0, 7.0, 8.0 };

c_zdrot( 2, (void *)x, 1, (void *)Y, 1, 0.8, 0.6 );
```
The function accepts the following arguments:
- **N**: `[in] CBLAS_INT` number of indexed elements.
- **zx**: `[inout] void*` first input array.
- **strideX**: `[in] CBLAS_INT` index increment for `zx`.
- **zy**: `[inout] void*` second input array.
- **strideY**: `[in] CBLAS_INT` index increment for `zy`.
- **c**: `[in] double` cosine of the angle of rotation.
- **s**: `[in] double` sine of the angle of rotation.
```c
void c_zdrot( const CBLAS_INT N, void *X, const CBLAS_INT strideX, void *Y, const CBLAS_INT strideY, const double c, const double s );
```

</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/zdrot.h"
#include <stdio.h>

int main( void ) {
// Create strided arrays:
double zx[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };
double zy[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };

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

// Specify stride lengths:
const int strideX = 1;
const int strideY = -1;

// Copy elements:
c_zdrot( N, (void *)zx, strideX, (void *)zy, strideY, 0.8, 0.6 );

// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "zx[ %i ] = %lf + %lfj\n", i, zx[ i*2 ], zx[ (i*2)+1 ] );
printf( "zy[ %i ] = %lf + %lfj\n", i, zy[ i*2 ], zy[ (i*2)+1 ] );
}
}
```
</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
[zdrot]: http://www.netlib.org/lapack/explore-html/da/df6/group__complex__blas__level1.html
[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
[@stdlib/array/complex128]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/complex128
</section>
<!-- /.links -->
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Coverage Report

Package Statements Branches Functions Lines
blas/base/zdrot $\color{green}531/531$
$\color{green}+100.00\%$
$\color{green}17/17$
$\color{green}+100.00\%$
$\color{green}4/4$
$\color{green}+100.00\%$
$\color{green}531/531$
$\color{green}+100.00\%$

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

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