npm package: @stdlib/lapack-base-slacpy
Description: Copy all or part of a matrix A to another matrix B.
Author: The Stdlib Authors
Latest version: 0.1.1

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# slacpy

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Copy all or part of a matrix `A` to another matrix `B`.

<section class="installation">

## Installation

```bash
npm install @stdlib/lapack-base-slacpy
```

</section>

<section class="usage">

## Usage

```javascript
var slacpy = require( '@stdlib/lapack-base-slacpy' );
```

#### slacpy( order, uplo, M, N, A, LDA, B, LDB )

Copies all or part of a matrix `A` to another matrix `B`.

```javascript
var Float32Array = require( '@stdlib/array-float32' );

var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0 ] );
var B = new Float32Array( 4 );

slacpy( 'row-major', 'all', 2, 2, A, 2, B, 2 );
// B => <Float32Array>[ 1.0, 2.0, 3.0, 4.0 ]
```

The function has the following parameters:

-   **order**: storage layout.
-   **uplo**: specifies whether to copy the upper or lower triangular/trapezoidal part of a matrix `A`.
-   **M**: number of rows in `A`.
-   **N**: number of columns in `A`.
-   **A**: input [`Float32Array`][mdn-Float32Array].
-   **LDA**: stride of the first dimension of `A` (a.k.a., leading dimension of the matrix `A`).
-   **B**: output [`Float32Array`][mdn-Float32Array].
-   **LDB**: stride of the first dimension of `B` (a.k.a., leading dimension of the matrix `B`).

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 Float32Array = require( '@stdlib/array-float32' );

// Initial arrays...
var A0 = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var B0 = new Float32Array( 5 );

// Create offset views...
var A1 = new Float32Array( A0.buffer, A0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var B1 = new Float32Array( B0.buffer, B0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

slacpy( 'row-major', 'all', 2, 2, A1, 2, B1, 2 );
// B0 => <Float32Array>[ 0.0, 2.0, 3.0, 4.0, 5.0 ]
```

#### slacpy.ndarray( uplo, M, N, A, sa1, sa2, oa, B, sb1, sb2, ob )

Copies all or part of a matrix `A` to another matrix `B` using alternative indexing semantics.

```javascript
var Float32Array = require( '@stdlib/array-float32' );

var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0 ] );
var B = new Float32Array( [ 0.0, 0.0, 0.0, 0.0 ] );

slacpy.ndarray( 'all', 2, 2, A, 2, 1, 0, B, 2, 1, 0 );
// B => <Float32Array>[ 1.0, 2.0, 3.0, 4.0 ]
```

The function has the following parameters:

-   **uplo**: specifies whether to copy the upper or lower triangular/trapezoidal part of a matrix `A`.
-   **M**: number of rows in `A`.
-   **N**: number of columns in `A`.
-   **A**: input [`Float32Array`][mdn-Float32Array].
-   **sa1**: stride of the first dimension of `A`.
-   **sa2**: stride of the second dimension of `A`.
-   **oa**: starting index for `A`.
-   **B**: output [`Float32Array`][mdn-Float32Array].
-   **sb1**: stride of the first dimension of `B`.
-   **sb2**: stride of the second dimension of `B`.
-   **ob**: starting index for `B`.

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,

```javascript
var Float32Array = require( '@stdlib/array-float32' );

var A = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var B = new Float32Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

slacpy.ndarray( 'all', 2, 2, A, 2, 1, 1, B, 2, 1, 2 );
// B => <Float32Array>[ 0.0, 0.0, 2.0, 3.0, 4.0, 5.0 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   `slacpy()` corresponds to the [LAPACK][lapack] routine [`slacpy`][lapack-slacpy].

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var ndarray2array = require( '@stdlib/ndarray-base-to-array' );
var uniform = require( '@stdlib/random-array-discrete-uniform' );
var numel = require( '@stdlib/ndarray-base-numel' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var slacpy = require( '@stdlib/lapack-base-slacpy' );

var shape = [ 5, 8 ];
var order = 'row-major';
var strides = shape2strides( shape, order );

var N = numel( shape );

var A = uniform( N, -10, 10, {
    'dtype': 'float32'
});
console.log( ndarray2array( A, shape, strides, 0, order ) );

var B = uniform( N, -10, 10, {
    'dtype': 'float32'
});
console.log( ndarray2array( B, shape, strides, 0, order ) );

slacpy( order, 'all', shape[ 0 ], shape[ 1 ], A, strides[ 0 ], B, strides[ 0 ] );
console.log( ndarray2array( B, shape, strides, 0, order ) );
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
TODO
```

#### TODO

TODO.

```c
TODO
```

TODO

```c
TODO
```

</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
TODO
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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<section class="related">

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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[deno-url]: https://github.com/stdlib-js/lapack-base-slacpy/tree/deno
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[branches-url]: https://github.com/stdlib-js/lapack-base-slacpy/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/lapack-base-slacpy/main/LICENSE

[lapack]: https://www.netlib.org/lapack/explore-html/

[lapack-slacpy]: https://www.netlib.org/lapack/explore-html/d0/d9e/group__lacpy_gae51b1efa5e6cb69029e83a425e773607.html#gae51b1efa5e6cb69029e83a425e773607

[mdn-float32array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float32Array

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

</section>

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