Zeros

NEWS.md

@@ -97,6 +97,8 @@ Library improvements
     That is, not every member of the input iterable will be visited if a `true` (in the case of `any`) or
     `false` (in the case of `all`) value is found, and `mapreduce` will visit all members of the iterable.
 
+  * Additional methods for `ones` and `zeros` functions to support the same signature as the `similar` function ([#19635]).
+
 Compiler/Runtime improvements
 -----------------------------
 

base/array.jl

@@ -207,9 +207,15 @@ fill(v, dims::Integer...) = fill!(Array{typeof(v)}(dims...), v)
 
 for (fname, felt) in ((:zeros,:zero), (:ones,:one))
     @eval begin
-        ($fname)(T::Type, dims...)       = fill!(Array{T}(dims...), ($felt)(T))
-        ($fname)(dims...)                = fill!(Array{Float64}(dims...), ($felt)(Float64))
-        ($fname){T}(A::AbstractArray{T}) = fill!(similar(A), ($felt)(T))
+        function ($fname)(a::AbstractArray, T::Type=eltype(a), dims::Tuple=size(a))
+            fill!(similar(a,T,dims), $felt(T))
+        end
+        ($fname)(T::Type, dims::Tuple) = ($fname)(Array{T}(dims...), T, dims)
+        ($fname)(dims::Tuple) = ($fname)(Float64, dims)
+
+        ($fname)(a::AbstractArray,T::Type,dims::DimOrInd...) = ($fname)(a,T,dims)
+        ($fname)(T::Type,dims::DimOrInd...) = ($fname)(T,dims)
+        ($fname)(dims::DimOrInd...) = ($fname)(dims)
     end
 end
 

base/docs/helpdb/Base.jl

@@ -564,9 +564,10 @@ julia> ones(Complex128, 2, 3)
 ones(t,dims)
 
 """
-    ones(A)
+    ones(A::AbstractArray, T=eltype(A)::Type, dims=size(A)::DimOrInd)
 
-Create an array of all ones with the same element type and shape as `A`.
+Create an array of all ones with the same layout as `A`. Element type and size
+can optionally be adjusted.
 
 ```jldoctest
 julia> A = [1 2; 3 4]
@@ -578,6 +579,17 @@ julia> ones(A)
 2×2 Array{Int64,2}:
  1  1
  1  1
+
+ julia> ones(A, Float64)
+2×2 Array{Float64,2}:
+ 1.  1.
+ 1.  1.
+
+ julia> ones(A, Bool, (3,))
+ 3-element Array{Bool,1}:
+  true
+  true
+  true
 ```
 """
 ones(A)
@@ -2704,9 +2716,10 @@ julia> zeros(Int8, 2, 3)
 zeros(t,dims)
 
 """
-    zeros(A)
+    zeros(A::AbstractArray, T=eltype(A)::Type, dims=size(A)::DimOrInd)
 
-Create an array of all zeros with the same element type and shape as `A`.
+Create an array of all zeros with the same layout as `A`. Element type and size
+can optionally be adjusted.
 
 ```jldoctest
 julia> A = [1 2; 3 4]
@@ -2718,6 +2731,17 @@ julia> zeros(A)
 2×2 Array{Int64,2}:
  0  0
  0  0
+
+ julia> zeros(A, Float64)
+2×2 Array{Float64,2}:
+ 0.0  0.0
+ 0.0  0.0
+
+ julia> zeros(A, Bool, (3,))
+ 3-element Array{Bool,1}:
+  false
+  false
+  false
 ```
 """
 zeros(A)

test/arrayops.jl

@@ -1927,6 +1927,40 @@ using TestHelpers.OAs
     @test accumulate(op, [10 20 30], 2) == [10 op(10, 20) op(op(10, 20), 30)] == [10 40 110]
 end
 
+@testset "zeros and ones" begin
+    @test ones([1,2], Float64, (2,3)) == ones(2,3)
+    @test ones(2) == ones(Int, 2) == ones([2,3], Float32, 2) ==  [1,1]
+    @test isa(ones(2), Vector{Float64})
+    @test isa(ones(Int, 2), Vector{Int})
+    @test isa(ones([2,3], Float32, 2), Vector{Float32})
+
+    function test_zeros(arr, T, s)
+        @test all(arr .== 0)
+        @test isa(arr, T)
+        @test size(arr) == s
+    end
+    test_zeros(zeros(2),     Vector{Float64}, (2,))
+    test_zeros(zeros(2,3),   Matrix{Float64}, (2,3))
+    test_zeros(zeros((2,3)), Matrix{Float64}, (2,3))
+
+    test_zeros(zeros(Int, 6),      Vector{Int}, (6,))
+    test_zeros(zeros(Int, 2, 3),   Matrix{Int}, (2,3))
+    test_zeros(zeros(Int, (2, 3)), Matrix{Int}, (2,3))
+
+    test_zeros(zeros([1 2; 3 4]), Matrix{Int}, (2, 2))
+    test_zeros(zeros([1 2; 3 4], Float64), Matrix{Float64}, (2, 2))
+
+    zs = zeros(SparseMatrixCSC([1 2; 3 4]), Complex{Float64}, (2,3))
+    test_zeros(zs, SparseMatrixCSC{Complex{Float64}}, (2, 3))
+
+    @testset "#19265" begin
+        @test_throws MethodError zeros(Float64, [1.])
+        x = [1.]
+        test_zeros(zeros(x, Float64), Vector{Float64}, (1,))
+        @test x == [1.]
+    end
+end
+
 # issue #11053
 type T11053
     a::Float64