sqrt

sqrt computes common and modular square roots. Pass it a single number and it is Javascript's standard Math.sqrt. Use it with two integers a and p (p prime) to compute the integer square roots of a modulo p.

Modular square roots can be computed for integers in Javascript's number range or for arbitrary-precision BigInts.

Installation

sqrt is a npm package:

    $ npm install @acransac/sqrt

It can be uninstalled with:

    $ npm uninstall @acransac/sqrt

Usage

    import sqrt from '@acransac/sqrt';

    sqrt(25); // 5

    sqrt(123.45); // 11.110805551354051 

    sqrt(3, 11); // [5, 6]

    sqrt(1267650600228227149696889519974n, 1267650600228229401496703205223n); // [403392878153763115700000692025n, 864257722074466285796702513198n]

API

sqrt(x[,modulo])

• x <number> | <bigint>
• modulo <number> | <bigint> Default: undefined
• Returns: <number> | <number[]> | <bigint[]> | <NaN>

Compute the common square root if only x is provided. The latter should be a number and a number or NaN is returned. It is Math.sqrt.

Compute the square root of x modulo modulo if both arguments are provided. x and modulo can either be numbers or bigints but they should be of the same type. x should range from 0 to modulo included. modulo should be at least 2 and prime. The pair of roots is returned in ascending order with the same integer type as the inputs. If there is no root or the computation failed or the inputs are invalid NaN is returned. If modulo is not prime, sqrt either returns NaN or hangs.