feat: add blas/ext/base/cediff

lib/node_modules/@stdlib/blas/ext/base/cediff/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.
+
+-->
+
+# cediff
+
+> Calculate the differences between consecutive elements of a single-precision complex floating-point strided array.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var cediff = require( '@stdlib/blas/ext/base/cediff' );
+```
+
+<!-- lint disable maximum-heading-length -->
+
+#### cediff( N, x, strideX, N1, prepend, strideP, N2, append, strideA, out, strideOut )
+
+<!-- lint enable maximum-heading-length -->
+
+Calculates the differences between consecutive elements of a single-precision complex floating-point strided array.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Complex64Array = require( '@stdlib/array/complex64' );
+
+var x = new Complex64Array( [ 2.0, -2.0, 4.0, -4.0, 6.0, -6.0, 8.0, -8.0, 10.0, -10.0 ] );
+var p = new Complex64Array( [ 1.0, -1.0 ] );
+var a = new Complex64Array( [ 11.0, -11.0 ] );
+var out = new Complex64Array( 6 );
+
+cediff( x.length, x, 1, 1, p, 1, 1, a, 1, out, 1 );
+// out => <Complex64Array>[ 1.0, -1.0, 2.0, -2.0, 2.0, -2.0, 2.0, -2.0, 2.0, -2.0, 11.0, -11.0 ]
+```
+
+The function has the following parameters:
+
+-   **N**: number of indexed elements.
+-   **x**: input [`Complex64Array`][@stdlib/array/complex64].
+-   **strideX**: stride length for `x`.
+-   **N1**: number of indexed elements to `prepend`.
+-   **prepend**: a [`Complex64Array`][@stdlib/array/complex64] containing values to prepend after computing differences.
+-   **strideP**: stride length for `prepend`.
+-   **N2**: number of indexed elements to `append`.
+-   **append**: a [`Complex64Array`][@stdlib/array/complex64] containing values to append after computing differences.
+-   **strideA**: stride length for `append`.
+-   **out**: output [`Complex64Array`][@stdlib/array/complex64]. Must have `N + N1 + N2 - 1` indexed 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 the difference between every other element:
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Complex64Array = require( '@stdlib/array/complex64' );
+
+var x = new Complex64Array( [ 2.0, -2.0, 4.0, -4.0, 6.0, -6.0, 8.0, -8.0, 10.0, -10.0 ] );
+var p = new Complex64Array( [ 1.0, -1.0 ] );
+var a = new Complex64Array( [ 11.0, -11.0 ] );
+var out = new Complex64Array( 4 );
+
+cediff( 3, x, 2, 1, p, 1, 1, a, 1, out, 1 );
+// out => <Complex64Array>[ 1.0, -1.0, 4.0, -4.0, 4.0, -4.0, 11.0, -11.0 ]
+```
+
+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' );
+
+// Initial array...
+var x0 = new Complex64Array( [ 2.0, -2.0, 4.0, -4.0, 6.0, -6.0, 8.0, -8.0, 10.0, -10.0 ] );
+
+// Create an offset view...
+var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+var p = new Complex64Array( [ 1.0, -1.0 ] );
+var a = new Complex64Array( [ 11.0, -11.0 ] );
+var out = new Complex64Array( 5 );
+
+cediff( x1.length, x1, 1, 1, p, 1, 1, a, 1, out, 1 );
+// out => <Complex64Array>[ 1.0, -1.0, 2.0, -2.0, 2.0, -2.0, 2.0, -2.0, 11.0, -11.0 ]
+```
+
+<!-- lint disable maximum-heading-length -->
+
+#### cediff.ndarray( N, x, strideX, offsetX, N1, prepend, strideP, offsetP, N2, append, strideA, offsetA, out, strideOut, offsetOut )
+
+<!-- lint enable maximum-heading-length -->
+
+Calculates the differences between consecutive elements of a single-precision complex floating-point strided array using alternative indexing semantics.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Complex64Array = require( '@stdlib/array/complex64' );
+
+var x = new Complex64Array( [ 2.0, -2.0, 4.0, -4.0, 6.0, -6.0, 8.0, -8.0, 10.0, -10.0 ] );
+var p = new Complex64Array( [ 1.0, -1.0 ] );
+var a = new Complex64Array( [ 11.0, -11.0 ] );
+var out = new Complex64Array( 6 );
+
+cediff.ndarray( x.length, x, 1, 0, 1, p, 1, 0, 1, a, 1, 0, out, 1, 0 );
+// out => <Complex64Array>[ 1.0, -1.0, 2.0, -2.0, 2.0, -2.0, 2.0, -2.0, 2.0, -2.0, 11.0, -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 parameters support indexing semantics based on starting indices. For example, to access only the last three elements:
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Complex64Array = require( '@stdlib/array/complex64' );
+
+var x = new Complex64Array( [ 2.0, -2.0, 4.0, -4.0, 6.0, -6.0, 8.0, -8.0, 10.0, -10.0 ] );
+var p = new Complex64Array( [ 1.0, -1.0 ] );
+var a = new Complex64Array( [ 11.0, -11.0 ] );
+var out = new Complex64Array( 4 );
+
+cediff.ndarray( 3, x, 1, x.length-3, 1, p, 1, 0, 1, a, 1, 0, out, 1, 0 );
+// out => <Complex64Array>[ 1.0, -1.0, 2.0, -2.0, 2.0, -2.0, 11.0, -11.0 ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   If `N + N1 + N2 <= 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 Complex64Array = require( '@stdlib/array/complex64' );
+var cediff = require( '@stdlib/blas/ext/base/cediff' );
+
+var xbuf = discreteUniform( 20, -100, 100, {
+    'dtype': 'float32'
+});
+var x = new Complex64Array( xbuf.buffer );
+console.log( 'Input array: ', x );
+
+var pbuf = discreteUniform( 4, -100, 100, {
+    'dtype': 'float32'
+});
+var p = new Complex64Array( pbuf.buffer );
+console.log( 'Prepend array: ', p );
+
+var abuf = discreteUniform( 4, -100, 100, {
+    'dtype': 'float32'
+});
+var a = new Complex64Array( abuf.buffer );
+console.log( 'Append array: ', a );
+
+var out = new Complex64Array( 13 );
+
+cediff( 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/cediff.h"
+```
+
+<!-- lint disable maximum-heading-length -->
+
+#### stdlib_strided_cediff( N, \*X, strideX, N1, \*Prepend, strideP, N2, \*Append, strideA, \*Out, strideOut )
+
+<!-- lint enable maximum-heading-length -->
+
+Calculates the differences between consecutive elements of a single-precision complex floating-point strided array.
+
+```c
+#include "stdlib/complex/float32/ctor.h"
+
+const float x[] = { 2.0f, -2.0f, 4.0f, -4.0f, 6.0f, -6.0f, 8.0f, -8.0f, 10.0f, -10.0f };
+const float p[] = { 1.0f, -1.0f };
+const float a[] = { 11.0f, -11.0f };
+float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
+
+stdlib_strided_cediff( 5, (const stdlib_complex64_t *)x, 1, 1, (const stdlib_complex64_t *)p, 1, 1, (const stdlib_complex64_t *)a, 1, (stdlib_complex64_t *)out, 1 );
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] stdlib_complex64_t*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+-   **N1**: `[in] CBLAS_INT` number of indexed elements to prepend.
+-   **Prepend**: `[in] stdlib_complex64_t*` array containing values to prepend after computing differences.
+-   **strideP**: `[in] CBLAS_INT` stride length for `Prepend`.
+-   **N2**: `[in] CBLAS_INT` number of indexed elements to append.
+-   **Append**: `[in] stdlib_complex64_t*` array containing values to append after computing differences.
+-   **strideA**: `[in] CBLAS_INT` stride length for `Append`.
+-   **Out**: `[out] stdlib_complex64_t*` output array. Must have `N + N1 + N2 - 1` elements.
+-   **strideOut**: `[in] CBLAS_INT` stride length for `Out`.
+
+```c
+void stdlib_strided_cediff( const CBLAS_INT N, const stdlib_complex64_t *X, const CBLAS_INT strideX, const CBLAS_INT N1, const stdlib_complex64_t *Prepend, const CBLAS_INT strideP, const CBLAS_INT N2, const stdlib_complex64_t *Append, const CBLAS_INT strideA, stdlib_complex64_t *Out, const CBLAS_INT strideOut );
+```
+
+<!-- lint disable maximum-heading-length -->
+
+#### stdlib_strided_cediff_ndarray( N, \*X, strideX, offsetX, N1, \*Prepend, strideP, offsetP, N2, \*Append, strideA, offsetA, \*Out, strideOut, offsetOut )
+
+<!-- lint enable maximum-heading-length -->
+
+Calculates the differences between consecutive elements of a single-precision complex floating-point strided array using alternative indexing semantics.
+
+```c
+#include "stdlib/complex/float32/ctor.h"
+
+const float x[] = { 2.0f, -2.0f, 4.0f, -4.0f, 6.0f, -6.0f, 8.0f, -8.0f, 10.0f, -10.0f };
+const float p[] = { 1.0f, -1.0f };
+const float a[] = { 11.0f, -11.0f };
+float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
+
+stdlib_strided_cediff_ndarray( 5, (const stdlib_complex64_t *)x, 1, 0, 1, (const stdlib_complex64_t *)p, 1, 0, 1, (const stdlib_complex64_t *)a, 1, 0, (stdlib_complex64_t *)out, 1, 0 );
+```
+
+The function accepts the following arguments:
+
+-   **N**: `[in] CBLAS_INT` number of indexed elements.
+-   **X**: `[in] stdlib_complex64_t*` input array.
+-   **strideX**: `[in] CBLAS_INT` stride length for `X`.
+-   **offsetX**: `[in] CBLAS_INT` starting index for `X`.
+-   **N1**: `[in] CBLAS_INT` number of indexed elements to prepend.
+-   **Prepend**: `[in] stdlib_complex64_t*` 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 indexed elements to append.
+-   **Append**: `[in] stdlib_complex64_t*` 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**: `[out] stdlib_complex64_t*` 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_cediff_ndarray( const CBLAS_INT N, const stdlib_complex64_t *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, const CBLAS_INT N1, const stdlib_complex64_t *Prepend, const CBLAS_INT strideP, const CBLAS_INT offsetP, const CBLAS_INT N2, const stdlib_complex64_t *Append, const CBLAS_INT strideA, const CBLAS_INT offsetA, stdlib_complex64_t *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/cediff.h"
+#include "stdlib/complex/float32/ctor.h"
+#include <stdio.h>
+
+int main( void ) {
+    // Create a strided array of interleaved real and imaginary components:
+    const float x[] = { 1.0f, -1.0f, 2.0f, -2.0f, 3.0f, -3.0f, 4.0f, -4.0f };
+
+    // Define a list of values to prepend:
+    const float p[] = { 0.0f, 0.0f };
+
+    // Define a list of values to append:
+    const float a[] = { 5.0f, -5.0f };
+
+    // Define an output array:
+    float out[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
+
+    // Compute the differences between consecutive elements:
+    stdlib_strided_cediff( 4, (const stdlib_complex64_t *)x, 1, 1, (const stdlib_complex64_t *)p, 1, 1, (const stdlib_complex64_t *)a, 1, (stdlib_complex64_t *)out, 1 );
+
+    // Print the result:
+    for ( int i = 0; i < 10; 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/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
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->