Skip to content

feat: add blas/ext/base/cwxsa #12691

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
anandkaranubc wants to merge 1 commit into
base: develop
Choose a base branch
from
+5,017 −0
Open

feat: add blas/ext/base/cwxsa #12691

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
374 changes: 374 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/cwxsa/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,374 @@
<!--

@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.

-->

# cwxsa

> Subtract a scalar constant from each element in a single-precision complex floating-point strided array `x` and assign the results to elements in a single-precision complex floating-point strided array `w`.

<section class="intro">

This BLAS extension implements the operation

<!-- <equation class="equation" label="eq:wxsa" align="center" raw="\mathbf{w} = \mathbf{x} - \alpha" alt="Equation for wxsa operation."> -->

```math
\mathbf{w} = \mathbf{x} - \alpha
```

<!-- </equation> -->

This API is complementary to the package [`@stdlib/blas/ext/base/cxsa`][@stdlib/blas/ext/base/cxsa], which performs an in-place update.

</section>

<!-- /.intro -->

<section class="usage">

## Usage

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

#### cwxsa( N, alpha, x, strideX, w, strideW )

Subtracts a scalar constant from each element in a single-precision complex floating-point strided array `x` and assigns the results to elements in a single-precision complex floating-point strided array `w`.

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var w = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
var alpha = new Complex64( 5.0, 3.0 );

cwxsa( x.length, alpha, x, 1, w, 1 );
// w => <Complex64Array>[ -4.0, -1.0, -2.0, 1.0, 0.0, 3.0, 2.0, 5.0 ]
```

The function has the following parameters:

- **N**: number of indexed elements.
- **alpha**: scalar constant.
- **x**: input [`Complex64Array`][@stdlib/array/complex64].
- **strideX**: stride length for `x`.
- **w**: output [`Complex64Array`][@stdlib/array/complex64].
- **strideW**: stride length for `w`.

The `N` and stride parameters determine which elements in the strided arrays are accessed at runtime. For example, to subtract `alpha` from every other element in `x` and assign the results to every other element in `w`:

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var w = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var alpha = new Complex64( 5.0, 3.0 );

cwxsa( 2, alpha, x, 2, w, 2 );
// w => <Complex64Array>[ -4.0, -1.0, 0.0, 0.0, 0.0, 3.0, 0.0, 0.0 ]
```

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

<!-- eslint-disable max-len -->

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );

// Initial arrays...
var x0 = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 ] );
var w0 = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var w1 = new Complex64Array( w0.buffer, w0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

var alpha = new Complex64( 5.0, 3.0 );

cwxsa( 3, alpha, x1, 1, w1, 1 );
// w0 => <Complex64Array>[ 0.0, 0.0, 0.0, 0.0, -2.0, 1.0, 0.0, 3.0, 2.0, 5.0 ]
```

#### cwxsa.ndarray( N, alpha, x, strideX, offsetX, w, strideW, offsetW )

Subtracts a scalar constant from each element in a single-precision complex floating-point strided array `x` and assigns the results to elements in a single-precision complex floating-point strided array `w` using alternative indexing semantics.

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var w = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
var alpha = new Complex64( 5.0, 3.0 );

cwxsa.ndarray( x.length, alpha, x, 1, 0, w, 1, 0 );
// w => <Complex64Array>[ -4.0, -1.0, -2.0, 1.0, 0.0, 3.0, 2.0, 5.0 ]
```

The function has the following additional parameters:

- **offsetX**: starting index for `x`.
- **offsetW**: starting index for `w`.

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 subtract `alpha` from the last three elements of `x` and assign the results to the last three elements of `w`:

<!-- eslint-disable max-len -->

```javascript
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 ] );
var w = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var alpha = new Complex64( 5.0, 3.0 );

cwxsa.ndarray( 3, alpha, x, 1, x.length-3, w, 1, w.length-3 );
// w => <Complex64Array>[ 0.0, 0.0, 0.0, 0.0, 0.0, 3.0, 2.0, 5.0, 4.0, 7.0 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

- If `N <= 0`, both functions return `w` unchanged.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var Complex64Array = require( '@stdlib/array/complex64' );
var Complex64 = require( '@stdlib/complex/float32/ctor' );
var logEach = require( '@stdlib/console/log-each' );
var cwxsa = require( '@stdlib/blas/ext/base/cwxsa' );

var xbuf = discreteUniform( 20, -100, 100, {
'dtype': 'float32'
});
var wbuf = discreteUniform( 20, -100, 100, {
'dtype': 'float32'
});
var x = new Complex64Array( xbuf.buffer );
var w = new Complex64Array( wbuf.buffer );
var alpha = new Complex64( 5.0, 3.0 );

cwxsa( x.length, alpha, x, 1, w, 1 );
logEach( '%s', w );
```

</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/cwxsa.h"
```

#### stdlib_strided_cwxsa( N, alpha, \*X, strideX, \*W, strideW )

Subtracts a scalar constant from each element in a single-precision complex floating-point strided array `X` and assigns the results to elements in a single-precision complex floating-point strided array `W`.

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

const float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
float w[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
const stdlib_complex64_t alpha = stdlib_complex64( 5.0f, 3.0f );

stdlib_strided_cwxsa( 4, alpha, (const stdlib_complex64_t *)x, 1, (stdlib_complex64_t *)w, 1 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **alpha**: `[in] stdlib_complex64_t` scalar constant.
- **X**: `[in] stdlib_complex64_t*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **W**: `[out] stdlib_complex64_t*` output array.
- **strideW**: `[in] CBLAS_INT` stride length for `W`.

```c
void stdlib_strided_cwxsa( const CBLAS_INT N, const stdlib_complex64_t alpha, const stdlib_complex64_t *X, const CBLAS_INT strideX, stdlib_complex64_t *W, const CBLAS_INT strideW );
```

<!-- lint disable maximum-heading-length -->

#### stdlib_strided_cwxsa_ndarray( N, alpha, \*X, strideX, offsetX, \*W, strideW, offsetW )

<!-- lint enable maximum-heading-length -->

Subtracts a scalar constant from each element in a single-precision complex floating-point strided array `X` and assigns the results to elements in a single-precision complex floating-point strided array `W` using alternative indexing semantics.

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

const float x[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f };
float w[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
const stdlib_complex64_t alpha = stdlib_complex64( 5.0f, 3.0f );

stdlib_strided_cwxsa_ndarray( 4, alpha, (const stdlib_complex64_t *)x, 1, 0, (stdlib_complex64_t *)w, 1, 0 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **alpha**: `[in] stdlib_complex64_t` scalar constant.
- **X**: `[in] stdlib_complex64_t*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **offsetX**: `[in] CBLAS_INT` starting index for `X`.
- **W**: `[out] stdlib_complex64_t*` output array.
- **strideW**: `[in] CBLAS_INT` stride length for `W`.
- **offsetW**: `[in] CBLAS_INT` starting index for `W`.

```c
void stdlib_strided_cwxsa_ndarray( const CBLAS_INT N, const stdlib_complex64_t alpha, const stdlib_complex64_t *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, stdlib_complex64_t *W, const CBLAS_INT strideW, const CBLAS_INT offsetW );
```

</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/ext/base/cwxsa.h"
#include "stdlib/complex/float32/ctor.h"
#include "stdlib/complex/float32/real.h"
#include "stdlib/complex/float32/imag.h"
#include <stdio.h>

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

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

// Specify strides:
const int strideX = 1;
const int strideW = 1;

// Define a scalar constant:
stdlib_complex64_t alpha = stdlib_complex64( 5.0f, 3.0f );

// Subtract a constant from each element in `x` and assign to `w`:
stdlib_strided_cwxsa( N, alpha, x, strideX, w, strideW );

// Print the result:
for ( int i = 0; i < N; i++ ) {
printf( "w[ %i ] = %f + %fi\n", i, stdlib_complex64_real( w[ i ] ), stdlib_complex64_imag( w[ i ] ) );
}
}
```

</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

[@stdlib/blas/ext/base/cxsa]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/blas/ext/base/cxsa

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

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

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

</section>

<!-- /.links -->
Loading
Loading