### 8 releases

0.1.7 | Nov 23, 2023 |
---|---|

0.1.6 | Nov 23, 2023 |

0.1.5 | Oct 1, 2020 |

0.1.4 | Jan 26, 2020 |

0.1.1 | Mar 14, 2017 |

#**157** in Math

**104** downloads per month

**MIT**license

10KB

166 lines

# pihex

Arbitrary place hexadecimal digits viewer of pi written in Rust. The library is based on the Bailey-Borwein-Plouffe formula (BBP formula) and Bellard's formula.

` ``$`` pihex`
`0:`` 243f 6a88 85a3 08d3 1319 8a2e 0370 7344`
`$`` pihex 1`
`2:`` 3f6a 8885 a308 d313 198a 2e03 7073 44a4`
`$`` pihex 4`
`4:`` 6a88 85a3 08d3 1319 8a2e 0370 7344 a409`
`$`` pihex 8`
`128:`` 9216 d5d9 8979 fb1b d131 0ba6 98df b5ac`
`$`` pihex 65536`
`65536:`` 3004 3414 c926 7212 d7fb 8a3f fc7c 7002`
`$`` pihex 1000000`
`1000000:`` 6c65 e52c b459 3500 50e4 bb17 8f4c 67a0`
`$`` pihex 10000000`
`10000000:`` 7af5 863e fed8 de97 033c d0f6 b80a 3d26`
`$`` pihex 100000000 ``#`` defaults to BBP formula
100000000: cb84 0e21 926e c5ae 0d2f 3405 1045 93cb
$ pihex --formula=bellard 100000000 # yields the same result but faster than BBP formula
100000000: cb84 0e21 926e c5ae 0d2f 3405 1045 93cb
`

Refer to

for further details.`pihex --help`

## Installation

### Homebrew

`brew`` install itchyny/tap/pihex`

### Build from source

`git`` clone https://github.com/itchyny/pihex`
`cd`` pihex`
`cargo`` install`` --`path .
`export` `PATH``=``$``PATH`:`$``HOME`/.cargo/bin

## Author

itchyny (https://github.com/itchyny)

## License

This software is released under the MIT License, see LICENSE.

## Disclaimer

I tested very carefully but this software does not always answer correctly due to the floating-point arithmetic inaccuracy. If there's a place with over 53bit zeros in binary representation of pi (I'm not sure where it is), we never ensure the answer calculated by double-precision floating-point numbers is correct. Therefore when you use this software, be careful the answer is not suffered from floating-point calculation errors. If the successive digits in hexadecimal representation repeat '0' or 'f' over 13 times, it's highly inaccurate due to this calculation errors.

## References

- David H. Bailey, Peter Borwein, and Simon Plouffe, On the Rapid Computation of Various Polylogarithmic Constants, Mathematics of Computation 66, 903-913, 1997.
- David H. Bailey, The BBP Algorithm for Pi, September 17, 2006.
- Fabrice Bellard, A new formula to compute the n'th binary digit of pi, 1997.

#### Dependencies

~1.3–1.8MB

~34K SLoC