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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!

dswap

NPM version Build Status Coverage Status

Interchange two double-precision floating-point vectors.

Usage

import dswap from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-dswap@deno/mod.js';

dswap( x, y[, dim] )

Interchanges two double-precision floating-point vectors x and y.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@deno/mod.js';

var x = array( new Float64Array( [ 4.0, 2.0, -3.0, 5.0, -1.0 ] ) );
var y = array( new Float64Array( [ 2.0, 6.0, -1.0, -4.0, 8.0 ] ) );

dswap( x, y );

var xbuf = x.data;
// returns <Float64Array>[ 2.0, 6.0, -1.0, -4.0, 8.0 ]

var ybuf = y.data;
// returns <Float64Array>[ 4.0, 2.0, -3.0, 5.0, -1.0 ]

The function has the following parameters:

  • x: a non-zero-dimensional ndarray whose underlying data type is float64. Must have the same shape as y.
  • y: a non-zero-dimensional ndarray whose underlying data type is float64. Must have the same shape as x.
  • dim: dimension along which to interchange vectors. Must be a negative integer. Negative indices are resolved relative to the last array dimension, with the last dimension corresponding to -1. Default: -1.

For multi-dimensional input ndarrays, the function performs batched computation, such that the function interchanges each pair of vectors in x and y according to the specified dimension index.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@deno/mod.js';
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@deno/mod.js';

var opts = {
    'shape': [ 2, 3 ]
};
var x = array( new Float64Array( [ 4.0, 2.0, -3.0, 5.0, -1.0, 3.0 ] ), opts );
var y = array( new Float64Array( [ 2.0, 6.0, -1.0, -4.0, 8.0, 2.0 ] ), opts );

var v1 = x.get( 0, 0 );
// returns 4.0

var v2 = y.get( 0, 0 );
// returns 2.0

dswap( x, y );

v1 = x.get( 0, 0 );
// returns 2.0

v2 = y.get( 0, 0 );
// returns 4.0

Notes

  • Both input ndarrays must have the same shape.
  • Negative indices are resolved relative to the last ndarray dimension, with the last dimension corresponding to -1.
  • For multi-dimensional ndarrays, batched computation effectively means swapping all of x with all of y; however, the choice of dim will significantly affect performance. For best performance, specify a dim which best aligns with the memory layout of provided ndarrays.
  • dswap() provides a higher-level interface to the BLAS level 1 function dswap.

Examples

import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@deno/mod.js';
import ndarray2array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-to-array@deno/mod.js';
import array from 'https://cdn.jsdelivr.net/gh/stdlib-js/ndarray-array@deno/mod.js';
import dswap from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-dswap@deno/mod.js';

var opts = {
    'dtype': 'float64'
};

var x = array( discreteUniform( 10, 0, 100, opts ), {
    'shape': [ 5, 2 ]
});
console.log( ndarray2array( x ) );

var y = array( discreteUniform( 10, 0, 10, opts ), {
    'shape': x.shape
});
console.log( ndarray2array( y ) );

dswap( x, y );
console.log( ndarray2array( x ) );
console.log( ndarray2array( y ) );

See Also

Notice

This package is part of stdlib, a standard library 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.

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.