Add sprand and sprand!

Author: lkdvos

Project.toml

@@ -11,6 +11,7 @@ Dictionaries = "85a47980-9c8c-11e8-2b9f-f7ca1fa99fb4"
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MapBroadcast = "ebd9b9da-f48d-417c-9660-449667d60261"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
 Accessors = "0.1.41"
@@ -21,6 +22,7 @@ Dictionaries = "0.4.3"
 FillArrays = "1.13.0"
 LinearAlgebra = "1.10"
 MapBroadcast = "0.1.5"
+Random = "1.10.0"
 SafeTestsets = "0.1"
 Suppressor = "0.2"
 Test = "1.10"

src/abstractsparsearrayinterface.jl

@@ -3,6 +3,7 @@ using DerivableInterfaces: DerivableInterfaces, @derive, @interface, AbstractArr
 # This is to bring `ArrayLayouts.zero!` into the namespace
 # since it is considered part of the sparse array interface.
 using ArrayLayouts: zero!
+using Random: Random, AbstractRNG, default_rng
 
 function eachstoredindex end
 function getstoredindex end
@@ -32,6 +33,48 @@ function densearray(a::AbstractArray)
   return Array(a)
 end
 
+@doc """
+    sprand([rng], [T::Type], dims; density::Real) -> A::SparseArrayDOK{T}
+
+Create a random size `dims` sparse array in which the probability of any element being stored is independently given by `density`.
+The optional `rng` argument specifies a random number generator, see also `Random`.
+The optional `T` argument specifies the element type, which defaults to `Float64`.
+
+See also [`sprand!`](@ref).
+""" sprand
+
+function sprand(::Type{T}, dims::Dims; density::Real=0.5) where {T}
+  return sprand(default_rng(), T, dims; density)
+end
+sprand(dims::Dims; density::Real=0.5) = sprand(default_rng(), Float64, dims; density)
+function sprand(rng::AbstractRNG, dims::Dims; density::Real=0.5)
+  return sprand(rng, Float64, dims; density)
+end
+function sprand(rng::AbstractRNG, ::Type{T}, dims::Dims; density::Real=0.5) where {T}
+  A = SparseArrayDOK{T}(undef, dims)
+  sprand!(rng, A; density)
+  return A
+end
+
+@doc """
+    sprand!([rng], A::AbstractArray; density::Real=0.5) -> A
+
+Overwrite part of an array with random entries, where the probability of overwriting is independently given by `density`.
+The optional `rng` argument specifies a random number generator, see also `Random`.
+
+See also [`sprand`](@ref).
+""" sprand!
+
+sprand!(A::AbstractArray; density::Real=0.5) = sprand!(default_rng(), A; density)
+function sprand!(rng::AbstractRNG, A::AbstractArray; density::Real=0.5)
+  rand_inds = Random.randsubseq(rng, eachindex(A), density)
+  rand_entries = rand(rng, eltype(A), length(rand_inds))
+
+  for (I, v) in zip(rand_inds, rand_entries)
+    A[I] = v
+  end
+end
+
 # Minimal interface for `SparseArrayInterface`.
 # Fallbacks for dense/non-sparse arrays.
 @interface ::AbstractArrayInterface isstored(a::AbstractArray, I::Int...) = true