1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77

/*!
# twofloat

This library provides an implementation of double-double arithmetic for the
Rust language. Note that this is not the same as the IEEE quadruple-precision
floating-point format. Instead, higher precision is obtained by representing
the value as the sum of two non-overlapping `f64` values.

## Usage

The basic type is `TwoFloat` which represents the sum of two non-overlapping
`f64` values, which may be initialized from a single `f64` or by calling a
constructor that performs an arithmetic operation on a pair of `f64` values.

```.rust
extern crate twofloat;
use twofloat::TwoFloat;

let a = TwoFloat::from(3.4);
let b = TwoFloat::new_add(1.0, 1.0e-300);
let c = TwoFloat::new_sub(1.0, 1.0e-300);
let d = TwoFloat::new_mul(5.0, 0.7);
let e = TwoFloat::new_div(1.0, 7.0);
```

Basic arithmetic operators and comparisons are available, together with the
utility functions `abs()`, `is_positive_sign()` and `is_negative_sign()`.
Mathematical functions are provided if the `math_funcs` feature is enabled
(this is enabled by default), though the implementations should be regarded
as preliminary.

Operations on non-finite values are not supported. At the moment this is not
automatically checked. The `is_valid()` method is provided for this purpose.

If the `serde_support` feature is enabled, serialization and deserialization
is possible through the Serde library.

## References

* Mioara Joldes, Jean-Michel Muller, Valentina Popescu. Tight and rigourous
  error bounds for basic building blocks of double-word arithmetic. ACM
  Transactions on Mathematical Software, Association for Computing Machinery,
  2017, 44 (2), pp.1 - 27. 10.1145/3121432. hal-01351529v3

* Alan H. Karp, Peter Markstein. High Precision Division and Square Root. ACM
  Transactions on Mathematical Software, Association for Computing Machinery,
  1997, 23 (4), pp. 561-589. 10.1145/279232.279237.

* S. Chevillard, M. Joldeș and C. Lauter. Sollya: an environment for the
  development of numerical codes. Mathematical Software - ICMS 2010, pp.
  28–31.
*/

#![forbid(unsafe_code)]
// Disable irrelevant lints

#![allow(clippy::clippy::approx_constant)]
#![allow(clippy::excessive_precision)]
#![allow(clippy::float_cmp)]
#![allow(clippy::suspicious_arithmetic_impl)]
#![allow(clippy::suspicious_op_assign_impl)]

#[cfg(test)]
mod test_util;

mod arithmetic;
mod base;

/// Basic mathematical constants.

///

/// Values determined using Sollya.

pub mod consts;

mod convert;
mod functions;

pub use base::{no_overlap, TwoFloat};
pub use convert::TwoFloatError;