https://github.com/kotet/bigfixed

Arbitrary-precision fixed point number that using std.bigint internally
https://github.com/kotet/bigfixed

dlang dub fixed-point

Last synced: 4 months ago
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Arbitrary-precision fixed point number that using std.bigint internally

• Host: GitHub
• URL: https://github.com/kotet/bigfixed
• Owner: kotet
• License: mit
• Created: 2017-05-28T05:51:53.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2017-08-13T21:19:53.000Z (almost 9 years ago)
• Last Synced: 2025-03-05T01:32:25.537Z (over 1 year ago)
• Topics: dlang, dub, fixed-point
• Language: D
• Size: 23.4 KB
• Stars: 0
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# bigfixed

[![Build Status](https://travis-ci.org/kotet/bigfixed.svg?branch=master)](https://travis-ci.org/kotet/bigfixed)

[![Coverage Status](https://coveralls.io/repos/github/kotet/bigfixed/badge.svg)](https://coveralls.io/github/kotet/bigfixed)

[![DUB](https://img.shields.io/dub/v/bigfixed.svg)](https://code.dlang.org/packages/bigfixed)

[![DUB](https://img.shields.io/dub/dt/bigfixed.svg)](https://code.dlang.org/packages/bigfixed)

This module provides arbitrary precision fixed-point arithmetic.

```d

// Return the square root of `n` to `prec` decimal places by a method of bisection.

string sqrt(ulong n, size_t prec)

{

    import std.conv : to;

    import std.math : ceil, log10;

    immutable size_t q = (prec / log10(2.0)).ceil.to!size_t() + 1;

    auto low = BigFixed(0, q);

    auto high = BigFixed(n, q);

    while ((high - low) != high.resolution) // BigFixed is integer internally.

    {

        immutable BigFixed mid = (high + low) >> 1; // Shift Expressions can be used.

        immutable bool isLess = (mid * mid) < n;

        if (isLess)

        {

            low = mid;

        }

        else

        {

            high = mid;

        }

    }

    return low.toDecimalString(prec);

}

// 10 digits before the 1,000th digit. See http://www.h2.dion.ne.jp/~dra/suu/chi2/heihoukon/2.html

immutable sqrt2_tail = "9518488472";

assert(sqrt(2, 1000)[$ - 10 .. $] == sqrt2_tail);

```

### Documentation

Run `dub fetch bigfixed && dub build bigfixed -b docs`.