Quartz 5

Julia

Properties2
tagslang, moc
aliases

3 min read

Julia

set

2022-05-27

setdiff(Set([1, 2]), Set([0])) # => {1, 2}
symdiff(Set([1, 2]), Set([0])) # => {1, 2, 0}

enum

# https://riptutorial.com/ja/julia-lang/example/23840/%E5%88%97%E6%8C%99%E5%9E%8B%E3%81%AE%E5%AE%9A%E7%BE%A9
import Base.*
 
@enum Suit ♣ ♦ ♥ ♠
@enum Rank ace=1 two three four five six seven eight nine ten jack queen king
 
struct Card
    rank::Rank
    suit::Suit
end
 
r::Int * s::Suit = Card(Rank(r), s)
 
Int(♦)
# => 1
 
string(Rank(4))
# => four
 
10♣
# => Card(ten::Rank = 10, ♣::Suit = 0)

@code_llvm

LLVM IR

@code_llvm sq(4)
# ;  @ REPL[1]:1 within `sq'
# define i64 @julia_sq_12223(i64) {
# top:
# ; ┌ @ intfuncs.jl:243 within `literal_pow'
# ; │┌ @ int.jl:54 within `*'
#     %1 = mul i64 %0, %0
# ; └└
#   ret i64 %1
# }

@code_native

Native codeが見れる

sq(x) = x * x
 
@code_llvm sq(4)
#         .section        __TEXT,__text,regular,pure_instructions
# ; ┌ @ REPL[1]:1 within `sq'
# ; │┌ @ intfuncs.jl:243 within `literal_pow'
# ; ││┌ @ REPL[1]:1 within `*'
#         imulq   %rdi, %rdi
# ; │└└
#         movq    %rdi, %rax
#         retq
#         nopl    (%rax,%rax)

Pkg

  • install deps
julia>]
Pkg> activate .
Pkg> instantiate
  • remove package dir
julia> rm(Pkg.dir("CUDA"); recursive=true)
julia> Pkg.resolve()

AST

ast = :(((x * x) * x) * (y * y))
 
# Expr has 
# - head::Symbol
# - args::Array{Symbol|Expr}
dump(ast)
# Expr
#   head: Symbol call
#   args: Array{Any}((3,))
#     1: Symbol *
#     2: Expr
#       head: Symbol call
#       args: Array{Any}((3,))
#         1: Symbol *
#         2: Expr
#           head: Symbol call
#           args: Array{Any}((3,))
#             1: Symbol *
#             2: Symbol x
#             3: Symbol x
#         3: Symbol x
#     3: Expr
#       head: Symbol call
#       args: Array{Any}((3,))
#         1: Symbol *
#         2: Symbol y
#         3: Symbol y
 
dump(ast.head == Symbol("call"))
# true
 
dump(ast.args[2].args[2])
# Expr
#   head: Symbol call
#   args: Array{Any}((3,))
#     1: Symbol *
#     2: Symbol x
#     3: Symbol x
 
# String to AST
@show Meta.parse("(x * x * x) * (y * y)")

Distributed

inbox

  • 2022-05-30 行列とかの表示は display(a) で

型

  • 動的型付け, 多相的
  • 実行時型
  • :: 型表明
function f(x)::Float64
  return 1.0
end
  • 抽象型
    • abstract type Hoge end
  • extends subtype
    • abstract type HogeInt <: Int64 end
  • トップ型: Any. ボトム型 Unit{}
  • 原始型
    • primitive type F16 <: AbstractFloat 16 end
  • 複合型(不変)
struct Foo
  bar::Int
  baz
end
 
foo = Foo(1, 2)
 
fieldnames(foo) # :bar, :baz
  • フィールドのないstructはシングルトン
struct NoFields end
NoFields() == NoFields()
  • 可変複合型
mutable struct MutableFoo
  bar::Int
end

  • 合併型

    • IntOrString = Union{Int, AbstractString}

  • パラメータ型

struct Point{T} 
  x::T
  y::T
end
  • Juliaの型パラメータは不変
    • Float64 < Real == true
    • Point{Float64} <: Point{Real} == false
function norm(p::Point{<:Real})
  sqrt(p.x ^ 2 + p.y ^ 2)
end
 
abstract type Pointy{T<:Real} end
 
struct Point2{T<:Real} <: Pointy{T}
  x::T
end
  • 値型
    • struct Val{T} end
  • null許容
    • a::Nullable{Int} = Nullable(1)
    • get(a)

参考文献

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