Infinite random sequences (#181)

* InfRandVector

* Remove export

* prefix

* add prefix to docstring example

* add prefix to docstring example

Author: DanielVandH

Project.toml

@@ -9,41 +9,45 @@ FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
 Infinities = "e1ba4f0e-776d-440f-acd9-e1d2e9742647"
 LazyArrays = "5078a376-72f3-5289-bfd5-ec5146d43c02"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
+[weakdeps]
+DSP = "717857b8-e6f2-59f4-9121-6e50c889abd2"
+Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+
+[extensions]
+InfiniteArraysDSPExt = "DSP"
+InfiniteArraysStatisticsExt = "Statistics"
+
 [compat]
 Aqua = "0.8"
 ArrayLayouts = "1.8"
 BandedMatrices = "1.0"
-BlockArrays = "1.0"
 Base64 = "1"
+BlockArrays = "1.0"
 DSP = "0.7"
+Distributions = "0.25"
 FillArrays = "1.0"
 Infinities = "0.1.1"
 LazyArrays = "2.0.2"
 LinearAlgebra = "1.6"
+Random = "1"
 SparseArrays = "1"
 Statistics = "1"
 Test = "1"
 julia = "1.10"
 
-[extensions]
-InfiniteArraysDSPExt = "DSP"
-InfiniteArraysStatisticsExt = "Statistics"
-
 [extras]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 BandedMatrices = "aae01518-5342-5314-be14-df237901396f"
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
 BlockArrays = "8e7c35d0-a365-5155-bbbb-fb81a777f24e"
 DSP = "717857b8-e6f2-59f4-9121-6e50c889abd2"
+Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Aqua", "Test", "BandedMatrices", "BlockArrays", "Statistics", "SparseArrays", "Base64", "DSP"]
-
-[weakdeps]
-DSP = "717857b8-e6f2-59f4-9121-6e50c889abd2"
-Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+test = ["Aqua", "Test", "BandedMatrices", "BlockArrays", "Statistics", "SparseArrays", "Base64", "DSP", "Distributions"]

src/InfiniteArrays.jl

@@ -10,7 +10,7 @@ import Base: *, +, -, /, <, ==, >, \, ≤, ≥, (:), @propagate_inbounds,
              cumsum, dataids, diff, div, eltype, fill, findfirst, first, floatrange, getindex, hcat,
              in, ind2sub_rs, intersect, inv, isempty, isinf, issorted, last, length, lt, max,
              maximum, minimum, mod, one, ones, parent, parentindices, permutedims, print_matrix, print_matrix_row,
-             print_matrix_vdots, promote_rule, reinterpret, reshape, reverse, searchsorted,
+             print_matrix_vdots, promote_rule, rand, reinterpret, reshape, reverse, searchsorted,
              searchsortedfirst, searchsortedlast, setindex!, show, show_circular, show_delim_array, sign,
              signbit, similar, size, sort, sort!, step, sum, tail,
              to_shape, transpose, unaliascopy, union, unitrange_last, unsafe_convert, unsafe_indices, unsafe_length,
@@ -42,12 +42,15 @@ import FillArrays: AbstractFill, Eye, Fill, Ones, RectDiagonal, Zeros, fill_resh
 import Infinities: InfiniteCardinal, Infinity, ∞
 
 import LazyArrays: AbstractCachedVector, ApplyLayout, CachedArray, CachedVector, InvColumnLayout,
-                   LazyArrayStyle, LazyLayout, LazyMatrix, PaddedColumns, _padded_sub_materialize, sub_paddeddata
+                   LazyArrayStyle, LazyLayout, LazyMatrix, PaddedColumns, _padded_sub_materialize, resizedata!, 
+                   sub_paddeddata
 
 import LinearAlgebra: AdjOrTrans, HermOrSym, diag, norm, norm1, norm2, normp
 
 import LazyArrays: AbstractPaddedLayout
 
+import Random: default_rng
+
 export ∞, ℵ₀, Hcat, Vcat, Zeros, Ones, Fill, Eye, BroadcastArray, cache
 import Base: unitrange, oneto
 
@@ -56,6 +59,7 @@ import Base: unitrange, oneto
 include("infrange.jl")
 include("infarrays.jl")
 include("reshapedarray.jl")
+include("infrand.jl")
 
 ##
 # Fill FillArrays

src/infrand.jl

@@ -0,0 +1,64 @@
+"""
+    InfRandVector([rng=default_rng()], [dist=Float64])
+
+Represents a random infinite sequence. The random number generator can be specified 
+by the first argument `rng`, which defaults to `Random.default_rng()`, and the distribution 
+to generate from can be specified using the `dist` argument, which defaults to `Float64`.
+
+```julia-repl
+julia> using InfiniteArrays
+
+julia> seq = InfiniteArrays.InfRandVector();
+
+julia> seq[1]
+0.6947847847152157
+
+julia> seq[1:5]
+5-element Vector{Float64}:
+ 0.6947847847152157
+ 0.49859004150722164
+ 0.31559745572937126
+ 0.5338596092137163
+ 0.14792462133894646
+
+julia> using Distributions, Random
+
+julia> seq = InfiniteArrays.InfRandVector(MersenneTwister(123), Normal(0.3, 1.7))
+ℵ₀-element InfRandVector{Float64, Normal{Float64}, MersenneTwister} with indices 1:∞:
+  2.3234553976766703
+  3.7819055032417075
+  2.242506534874238
+  1.0810065546920364
+ -0.3743544348018791
+ -0.8300113268258689
+  1.967645305489507
+  ⋮
+```
+"""
+mutable struct InfRandVector{T,D,RNG} <: AbstractCachedVector{T}
+    const rng::RNG
+    const dist::D
+    const data::Vector{T}
+    datasize::Int
+end
+function InfRandVector(rng=default_rng(), dist=Float64)
+    T = typeof(rand(copy(rng), dist))
+    _rng = copy(rng)
+    return InfRandVector{T,typeof(dist),typeof(_rng)}(_rng, dist, T[], 0)
+end
+Base.size(::InfRandVector) = (ℵ₀,)
+Base.axes(::InfRandVector) = (1:ℵ₀,)
+Base.length(::InfRandVector) = ℵ₀
+function resizedata!(seq::InfRandVector, inds)
+    newlen = maximum(inds)
+    curlen = length(seq.data)
+    newlen > curlen || return seq
+    resize!(seq.data, newlen)
+    # rand!(seq.rng, view(seq.data, curlen+1:newlen), seq.dist)
+    # ^ rand() is not actually sequential.. rand(Random.seed!(123), 1000) ≠ (rng = Random.seed!(123); [rand(rng) for _ in 1:1000])
+    for i in (curlen+1):newlen
+        seq.data[i] = rand(seq.rng, seq.dist)
+    end
+    seq.datasize = newlen
+    return seq
+end

test/runtests.jl

@@ -1,5 +1,5 @@
-using LinearAlgebra, SparseArrays, InfiniteArrays, Infinities, FillArrays, LazyArrays, Statistics, Test, Base64
-using BandedMatrices
+using LinearAlgebra, SparseArrays, InfiniteArrays, Infinities, FillArrays, LazyArrays, Random, Statistics, Test, Base64
+using BandedMatrices, Distributions
 import InfiniteArrays: InfUnitRange, InfStepRange, OneToInf, NotANumber, oneto, unitrange
 import LazyArrays: CachedArray, MemoryLayout, LazyLayout, DiagonalLayout, LazyArrayStyle, colsupport, DualLayout
 import BandedMatrices: _BandedMatrix, BandedColumns
@@ -1230,4 +1230,5 @@ end
 end
 
 include("test_infconv.jl")
-include("test_block.jl")
+include("test_block.jl")
+include("test_infrand.jl")

test/test_infrand.jl

@@ -0,0 +1,32 @@
+@testset "InfRandVector" begin
+    @testset "Default constructor" begin
+        Random.seed!(123)
+        seq = InfiniteArrays.InfRandVector()
+        val = seq[1]
+        @test seq[1] == val # constant 
+        @test seq[1:10000] == seq[1:10000]
+        @test seq[1] == val # didn't change after resizing
+        @inferred seq[1]
+        Random.seed!(123)
+        _seq = [rand() for _ in 1:1000]
+        @test seq[1:1000] == _seq[1:1000]
+        @test size(seq) == (ℵ₀,)
+        @test length(seq) == ℵ₀
+        @test axes(seq) == (1:ℵ₀,)
+    end
+
+    @testset "Providing an RNG and a distribution" begin
+        rng = MersenneTwister(123)
+        seq = InfiniteArrays.InfRandVector(rng, Float16)
+        rng2 = MersenneTwister(123)
+        @test seq[1:10000] == [rand(rng2, Float16) for _ in 1:10000]
+    end 
+
+    @testset "Distributions.jl" begin 
+        dist = Normal(0.3, 1.7) # do Normal{Float32} for example if you want that number type
+        rng = Xoshiro(5)
+        seq = InfiniteArrays.InfRandVector(rng, dist)
+        rng2 = Xoshiro(5)
+        @test seq[1:100] == [0.3 + 1.7randn(rng2) for _ in 1:100]
+    end
+end