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https://github.com/cjdoris/infinity.jl
Representation of infinity in Julia
https://github.com/cjdoris/infinity.jl
Last synced: 24 days ago
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Representation of infinity in Julia
- Host: GitHub
- URL: https://github.com/cjdoris/infinity.jl
- Owner: cjdoris
- License: mit
- Created: 2019-05-05T03:26:40.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2021-07-24T19:15:07.000Z (over 3 years ago)
- Last Synced: 2024-10-11T07:18:15.948Z (26 days ago)
- Language: Julia
- Homepage: https://juliahub.com/docs/Infinity/
- Size: 78.1 KB
- Stars: 14
- Watchers: 4
- Forks: 4
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Infinity.jl
[](https://juliahub.com/docs/Infinity/)
[](https://travis-ci.com/cjdoris/Infinity.jl)
[](https://codecov.io/gh/cjdoris/Infinity.jl)
Provides `∞ :: Infinite <: Real` representing positive infinity and `-∞` is negative infinity.
## Extended Types
### InfExtendedReal
Promotion between `Infinite` and some `T <: Real` will yield either:
* `T` itself if it can natively represent infinity (e.g. `Float64`, `Rational`); or
* `InfExtendedReal{T} <: Real` otherwise, which represents positive/negative infinity, or a finite value of type `T`. (See the examples.)
The following `Base` functions are extended for these types:
* Arithmetic: `typemin`, `typemax`, `+`, `-`, `*`, `/`
* Comparison: `==`, `<`, `≤`, `hash`, `signbit`, `sign`, `isfinite`, `isinf`, `isapprox`
* Conversion: `promote`, `convert`, `float`, `widen`, `big`
* Random: `rand(Infinite)`
Additionally there is a submodule `Utils` exporting infinity-related functions:
* `posinf(T)`, `neginf(T)`: positive or negative infinity as a `T` if possible, or else `nothing`
* `hasposinf(T)`, `hasneginf(T)`: true if `T` contains positive or negative infinity
* `hasinf(T)`: true if `T` contains both positive and negative infinity (this is used to decide to promote to `InfExtendedReal` or not)
* `isposinf(x)`, `isneginf(x)`: true if `x` is positive or negative infinity
### InfExtendedTime
Promotion between `Infinite` and some `T <: Dates.TimeType` will yield:
* `InfExtendedTime{T} <: Dates.TimeType`, which represents positive/negative infinity, or a finite value of type `T`. (See the examples.)
The following `Base` functions are extended for these types:
* Arithmetic: `typemin`, `typemax`, `T+Period`, `T-Period`
* Comparison: `==`. `<`, `≤`, `hash`, `isfinite`, `isinf`
* Conversion: `promote`, `convert`
## Installation
In Julia, type `]` then run
```julia
pkg> add Infinity
```
## Example
```julia
julia> using Infinity
julia> x = [1,2,3,∞,-1,-∞]
6-element Array{InfExtendedReal{Int64},1}:
InfExtendedReal{Int64}(1)
InfExtendedReal{Int64}(2)
InfExtendedReal{Int64}(3)
InfExtendedReal{Int64}(∞)
InfExtendedReal{Int64}(-1)
InfExtendedReal{Int64}(-∞)
julia> sort(x)
6-element Array{InfExtendedReal{Int64},1}:
InfExtendedReal{Int64}(-∞)
InfExtendedReal{Int64}(-1)
InfExtendedReal{Int64}(1)
InfExtendedReal{Int64}(2)
InfExtendedReal{Int64}(3)
InfExtendedReal{Int64}(∞)
julia> float(x)
6-element Array{Float64,1}:
1.0
2.0
3.0
Inf
-1.0
-Inf
julia> using Dates
julia> x = [Date(2012, 1, 1), Date(2013, 1, 1), Date(2013, 1, 2), ∞, Date(1987, 1, 1), -∞]
6-element Array{InfExtendedTime{Date},1}:
InfExtendedTime{Date}(2012-01-01)
InfExtendedTime{Date}(2013-01-01)
InfExtendedTime{Date}(2013-01-02)
InfExtendedTime{Date}(∞)
InfExtendedTime{Date}(1987-01-01)
InfExtendedTime{Date}(-∞)
julia> sort(x)
6-element Array{InfExtendedTime{Date},1}:
InfExtendedTime{Date}(-∞)
InfExtendedTime{Date}(1987-01-01)
InfExtendedTime{Date}(2012-01-01)
InfExtendedTime{Date}(2013-01-01)
InfExtendedTime{Date}(2013-01-02)
InfExtendedTime{Date}(∞)
julia> Day(1) + x
6-element Array{InfExtendedTime{Date},1}:
InfExtendedTime{Date}(2012-01-02)
InfExtendedTime{Date}(2013-01-02)
InfExtendedTime{Date}(2013-01-03)
InfExtendedTime{Date}(∞)
InfExtendedTime{Date}(1987-01-02)
InfExtendedTime{Date}(-∞)
```