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drrss

Calculate the square root of the residual sum of squares of two double-precision floating-point strided arrays.

The square root of the residual sum of squares is defined as

$$d = \sqrt{\sum_{i=0}^{N-1} (y_i - x_i)^2}$$

Usage

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

drrss( N, x, strideX, y, strideY )

Computes the square root of the residual sum of squares of two double-precision floating-point strided arrays.

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

var x = new Float64Array( [ 1.0, -2.0, 2.0 ] );
var y = new Float64Array( [ 1.0, 1.0, -4.0 ] );

var z = drrss( x.length, x, 1, y, 1 );
// returns ~6.7

The function has the following parameters:

• N: number of indexed elements.
• x: first input Float64Array.
• strideX: stride length for x.
• y: second input Float64Array.
• strideY: stride length for y.

The N and stride parameters determine which elements in strided arrays are accessed at runtime. For example, to compute the residual sum of squares of every other element in x and y

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

var x = new Float64Array( [ 1.0, 2.0, 2.0, -7.0, -2.0, 3.0, 4.0, 2.0 ] );
var y = new Float64Array( [ 2.0, 1.0, 2.0, 1.0, -2.0, 2.0, 3.0, 4.0 ] );

var z = drrss( x.length, x, 1, y, 1 );
// returns ~8.485

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

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

var x0 = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] );
var y0 = new Float64Array( [ 8.0, -2.0, 3.0, -2.0, 7.0, -2.0, 0.0, -1.0 ] );

var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var z = drrss( 4, x1, 2, y1, 2 );
// returns ~7.071

If N is less than or equal to 0, the function returns 0.

drrss.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )

Computes the square root of the residual sum of squares of two double-precision floating-point strided arrays using alternative indexing semantics.

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

var x = new Float64Array( [ 1.0, -2.0, 2.0 ] );
var y = new Float64Array( [ 1.0, 1.0, -4.0 ] );

var z = drrss.ndarray( x.length, x, 1, 0, y, 1, 0 );
// returns ~6.7

The function has the following additional parameters:

• offsetX: starting index for x.
• offsetY: starting index for y.

While 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 calculate the square root of the residual sum of squares for every other element in x and y starting from the second element

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

var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0, 6.0 ] );
var y = new Float64Array( [ 8.0, -2.0, 3.0, -2.0, 7.0, -2.0, 0.0, -1.0, 4.0 ] );

var z = drrss.ndarray( 4, x, 2, 1, y, 2, 1 );
// returns ~7.071

Notes

• If N <= 0, both functions return 0.0.

Examples

import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@deno/mod.js';
import drrss from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-drrss@deno/mod.js';

var opts = {
    'dtype': 'float64'
};
var x = discreteUniform( 10, -50, 50, opts );
console.log( x );

var y = discreteUniform( 10, -50, 50, opts );
console.log( y );

var d = drrss( x.length, x, 1, y, 1 );
console.log( d );

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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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.