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368 changes: 368 additions & 0 deletions lib/node_modules/@stdlib/blas/ext/base/sediff/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.

-->

# sediff

> Calculate the differences between consecutive elements of a single-precision floating-point strided array.

<section class="usage">

## Usage

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

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

#### sediff( N, x, strideX, N1, prepend, strideP, N2, append, strideA, out, strideOut )

Calculates the differences between consecutive elements of a single-precision floating-point strided array.

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

var x = new Float32Array( [ 2.0, 4.0, 6.0, 8.0, 10.0 ] );
var p = new Float32Array( [ 1.0 ] );
var a = new Float32Array( [ 11.0 ] );
var out = new Float32Array( 6 );

sediff( x.length, x, 1, 1, p, 1, 1, a, 1, out, 1 );

console.log( out );
// out => <Float32Array>[ 1.0, 2.0, 2.0, 2.0, 2.0, 11.0 ]
```

The function has the following parameters:

- **N**: number of indexed elements.
- **x**: input [`Float32Array`][@stdlib/array/float32].
- **strideX**: stride length for `x`.
- **N1**: number of elements to `prepend`.
- **prepend**: a [`Float32Array`][@stdlib/array/float32] containing values to prepend after computing differences.
- **strideP**: stride length for `prepend`.
- **N2**: number of elements to `append`.
- **append**: a [`Float32Array`][@stdlib/array/float32] containing values to append after computing differences.
- **strideA**: stride length for `append`.
- **out**: output [`Float32Array`][@stdlib/array/float32]. Must have `N + N1 + N2 - 1` elements.
- **strideOut**: stride length for `out`.

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

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

var x = new Float32Array( [ 2.0, 4.0, 6.0, 8.0, 10.0 ] );
var p = new Float32Array( [ 1.0 ] );
var a = new Float32Array( [ 11.0 ] );
var out = new Float32Array( 4 );

sediff( 3, x, 2, 1, p, 1, 1, a, 1, out, 1 );

console.log( out );
// out => <Float32Array>[ 1.0, 4.0, 4.0, 11.0 ]
```

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

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

// Initial array...
var x0 = new Float32Array( [ 2.0, 4.0, 6.0, 8.0, 10.0 ] );

// Create an offset view...
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var p = new Float32Array( [ 1.0 ] );
var a = new Float32Array( [ 11.0 ] );
var out = new Float32Array( 5 );

sediff( x1.length, x1, 1, 1, p, 1, 1, a, 1, out, 1 );

console.log( out );
// out => <Float32Array>[ 1.0, 2.0, 2.0, 2.0, 11.0 ]
```

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

#### sediff.ndarray( N, x, strideX, offsetX, N1, prepend, strideP, offsetP, N2, append, strideA, offsetA, out, strideOut, offsetOut )

Calculates the differences between consecutive elements of a single-precision floating-point strided array using alternative indexing semantics.

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

var x = new Float32Array( [ 2.0, 4.0, 6.0, 8.0, 10.0 ] );
var p = new Float32Array( [ 1.0 ] );
var a = new Float32Array( [ 11.0 ] );
var out = new Float32Array( 6 );

sediff.ndarray( x.length, x, 1, 0, 1, p, 1, 0, 1, a, 1, 0, out, 1, 0 );

console.log( out );
// out => <Float32Array>[ 1.0, 2.0, 2.0, 2.0, 2.0, 11.0 ]
```

The function has the following additional parameters:

- **offsetX**: starting index for `x`.
- **offsetP**: starting index for `prepend`.
- **offsetA**: starting index for `append`.
- **offsetOut**: starting index for `out`.

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 access only the last three elements:

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

var x = new Float32Array( [ 2.0, 4.0, 6.0, 8.0, 10.0 ] );
var p = new Float32Array( [ 1.0 ] );
var a = new Float32Array( [ 11.0 ] );
var out = new Float32Array( 4 );

sediff.ndarray( 3, x, 1, x.length-3, 1, p, 1, 0, 1, a, 1, 0, out, 1, 0 );

console.log( out );
// out => <Float32Array>[ 1.0, 2.0, 2.0, 11.0 ]
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

- If the sum of `N`, `N1`, and `N2` is less than or equal to `1`, both functions return the output array unchanged.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var Float32Array = require( '@stdlib/array/float32' );
var sediff = require( '@stdlib/blas/ext/base/sediff' );

var x = discreteUniform( 10, -100, 100, {
'dtype': 'float32'
});
console.log( 'Input array: ', x );

var p = discreteUniform( 2, -100, 100, {
'dtype': 'float32'
});
console.log( 'Prepend array: ', p );

var a = discreteUniform( 2, -100, 100, {
'dtype': 'float32'
});
console.log( 'Append array: ', a );

var out = new Float32Array( 13 );

sediff( x.length, x, 1, 2, p, 1, 2, a, 1, out, 1 );
console.log( 'Output', 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/ext/base/sediff.h"
```

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

#### stdlib_strided_sediff( N, \*X, strideX, N1, \*prepend, strideP, N2, \*append, strideA, \*Out, strideOut )

Calculates the differences between consecutive elements of a single-precision floating-point strided array.

```c
const float x[] = { 2.0f, 4.0f, 6.0f, 8.0f, 10.0f };
const float p[] = { 1.0f };
const float a[] = { 11.0f };
float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

stdlib_strided_sediff( 5, x, 1, 1, p, 1, 1, a, 1, out, 1 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] float*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **N1**: `[in] CBLAS_INT` number of elements in `prepend`.
- **prepend**: `[in] float*` array containing values to prepend after computing differences.
- **strideP**: `[in] CBLAS_INT` stride length for `prepend`.
- **N2**: `[in] CBLAS_INT` number of elements in `append`.
- **append**: `[in] float*` array containing values to append after computing differences.
- **strideA**: `[in] CBLAS_INT` stride length for `append`.
- **Out**: `[inout] float*` output array. Must have `N + N1 + N2 - 1` elements.
- **strideOut**: `[in] CBLAS_INT` stride length for `Out`.

```c
void stdlib_strided_sediff( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const CBLAS_INT N1, const float *prepend, const CBLAS_INT strideP, const CBLAS_INT N2, const float *append, const CBLAS_INT strideA, float *Out, const CBLAS_INT strideOut );
```

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

#### stdlib_strided_sediff_ndarray( N, \*X, strideX, offsetX, N1, \*prepend, strideP, offsetP, N2, \*append, strideA, offsetA, \*Out, strideOut, offsetOut )

Calculates the differences between consecutive elements of a single-precision floating-point strided array using alternative indexing semantics.

```c
const float x[] = { 2.0f, 4.0f, 6.0f, 8.0f, 10.0f };
const float p[] = { 1.0f };
const float a[] = { 11.0f };
float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

stdlib_strided_sediff_ndarray( 5, x, 1, 0, 1, p, 1, 0, 1, a, 1, 0, out, 1, 0 );
```

The function accepts the following arguments:

- **N**: `[in] CBLAS_INT` number of indexed elements.
- **X**: `[in] float*` input array.
- **strideX**: `[in] CBLAS_INT` stride length for `X`.
- **offsetX**: `[in] CBLAS_INT` starting index for `X`.
- **N1**: `[in] CBLAS_INT` number of elements in `prepend`.
- **prepend**: `[in] float*` array containing values to prepend after computing differences.
- **strideP**: `[in] CBLAS_INT` stride length for `prepend`.
- **offsetP**: `[in] CBLAS_INT` starting index for `prepend`.
- **N2**: `[in] CBLAS_INT` number of elements in `append`.
- **append**: `[in] float*` array containing values to append after computing differences.
- **strideA**: `[in] CBLAS_INT` stride length for `append`.
- **offsetA**: `[in] CBLAS_INT` starting index for `append`.
- **Out**: `[inout] float*` output array. Must have `N + N1 + N2 - 1` elements.
- **strideOut**: `[in] CBLAS_INT` stride length for `Out`.
- **offsetOut**: `[in] CBLAS_INT` starting index for `Out`.

```c
void stdlib_strided_sediff_ndarray( const CBLAS_INT N, const float *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const CBLAS_INT N1, const float *prepend, const CBLAS_INT strideP, const CBLAS_INT offsetP, const CBLAS_INT N2, const float *append, const CBLAS_INT strideA, const CBLAS_INT offsetA, float *Out, const CBLAS_INT strideOut, const CBLAS_INT offsetOut );
```

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

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

// Define prepend values:
const float p[] = { -1.0f };

// Define append values:
const float a[] = { 10.0f };

// Define output array:
float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

// Compute forward differences:
stdlib_strided_sediff( 8, x, 1, 1, p, 1, 1, a, 1, out, 1 );

// Print the result:
for ( int i = 0; i < 9; i++ ) {
printf( "out[ %i ] = %f\n", i, out[ 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/float32]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/float32

[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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