About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

dcircshift

Circularly shift the elements of a double-precision floating-point strided array by a specified number of positions.

Installation

npm install @stdlib/blas-ext-base-dcircshift

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var dcircshift = require( '@stdlib/blas-ext-base-dcircshift' );

dcircshift( N, k, x, strideX )

Circularly shifts the elements of a double-precision floating-point strided array by a specified number of positions.

var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );

dcircshift( x.length, 2, x, 1 );
// x => <Float64Array>[ 4.0, 5.0, 1.0, 2.0, 3.0 ]

The function has the following parameters:

• N: number of indexed elements.
• k: number of positions to shift.
• x: input Float64Array.
• strideX: stride length.

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

var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, 0.0, 2.0, 0.0, 3.0, 0.0, 4.0, 0.0 ] );

dcircshift( 4, 1, x, 2 );
// x => <Float64Array>[ 4.0, 0.0, 1.0, 0.0, 2.0, 0.0, 3.0, 0.0 ]

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Float64Array = require( '@stdlib/array-float64' );

// Initial array...
var x0 = new Float64Array( [ 0.0, 1.0, 2.0, 3.0, 4.0, 5.0 ] );

// Create an offset view...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Circularly shift elements in the view:
dcircshift( 5, 2, x1, 1 );
// x0 => <Float64Array>[ 0.0, 4.0, 5.0, 1.0, 2.0, 3.0 ]

dcircshift.ndarray( N, k, x, strideX, offsetX )

Circularly shifts the elements of a double-precision floating-point strided array by a specified number of positions using alternative indexing semantics.

var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );

dcircshift.ndarray( x.length, 2, x, 1, 0 );
// x => <Float64Array>[ 4.0, 5.0, 1.0, 2.0, 3.0 ]

The function has the following additional parameters:

• offsetX: starting index.

While 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 of the strided array:

var Float64Array = require( '@stdlib/array-float64' );

var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );

dcircshift.ndarray( 3, 1, x, 1, x.length-3 );
// x => <Float64Array>[ 1.0, 2.0, 3.0, 6.0, 4.0, 5.0 ]

Notes

• If N <= 0, both functions return the strided array unchanged.
• If k is a multiple of N, both functions return the strided array unchanged.
• If k > 0, elements are shifted to the right.
• If k < 0, elements are shifted to the left.

Examples

var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var dcircshift = require( '@stdlib/blas-ext-base-dcircshift' );

var x = discreteUniform( 10, -100, 100, {
    'dtype': 'float64'
});
console.log( x );

dcircshift( x.length, 3, x, 1 );
console.log( x );

---

C APIs

Usage

#include "stdlib/blas/ext/base/dcircshift.h"

stdlib_strided_dcircshift( N, k, *X, strideX )

Circularly shifts the elements of a double-precision floating-point strided array by a specified number of positions.

double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0 };

stdlib_strided_dcircshift( 5, 2, x, 1 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• k: [in] CBLAS_INT number of positions to shift.
• X: [inout] double* input array.
• strideX: [in] CBLAS_INT stride length.

void stdlib_strided_dcircshift( const CBLAS_INT N, const CBLAS_INT k, double *X, const CBLAS_INT strideX );

stdlib_strided_dcircshift_ndarray( N, k, *X, strideX, offsetX )

Circularly shifts the elements of a double-precision floating-point strided array by a specified number of positions using alternative indexing semantics.

double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0 };

stdlib_strided_dcircshift_ndarray( 5, 2, x, 1, 0 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• k: [in] CBLAS_INT number of positions to shift.
• X: [inout] double* input array.
• strideX: [in] CBLAS_INT stride length.
• offsetX: [in] CBLAS_INT starting index.

void stdlib_strided_dcircshift_ndarray( const CBLAS_INT N, const CBLAS_INT k, double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );

Examples

#include "stdlib/blas/ext/base/dcircshift.h"
#include <stdio.h>

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

    // Specify the number of elements:
    const int N = 8;

    // Specify the shift amount:
    const int k = 3;

    // Specify a stride:
    const int strideX = 1;

    // Perform the circular shift:
    stdlib_strided_dcircshift( N, k, x, strideX );

    // Print the result:
    for ( int i = 0; i < 8; i++ ) {
        printf( "x[ %i ] = %lf\n", i, x[ i ] );
    }
}

---

Notice

This package is part of 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, see the main project repository.

Community

---

License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.