Return float(T)[] so that refine_grid should be type stable

SpM-lab · Dec 12, 2024 · eee06e8 · eee06e8
1 parent 96bbdec
commit eee06e8
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Showing 2 changed files with 11 additions and 7 deletions.
diff --git a/src/_roots.jl b/src/_roots.jl
@@ -40,7 +40,7 @@ closeenough(a::T, b::T, ϵ) where {T<:AbstractFloat} = isapprox(a, b; rtol=0, at
 closeenough(a::T, b::T, _) where {T<:Integer} = a == b
 
 function refine_grid(grid::Vector{T}, ::Val{α}) where {T, α}
-    isempty(grid) && return grid
+    isempty(grid) && return float(T)[]
     n = length(grid)
     newn = α * (n - 1) + 1
     newgrid = Vector{float(T)}(undef, newn)

diff --git a/test/_roots.jl b/test/_roots.jl
@@ -6,7 +6,7 @@ using SparseIR
         @testset "Basic refinement" begin
             # Test with α = 2
             grid = [0.0, 1.0, 2.0]
-            refined = SparseIR.refine_grid(grid, Val(2))
+            refined = @inferred SparseIR.refine_grid(grid, Val(2))
             @test length(refined) == 5  # α * (n-1) + 1 = 2 * (3-1) + 1 = 5
             @test refined ≈ [0.0, 0.5, 1.0, 1.5, 2.0]
 
@@ -29,13 +29,13 @@ using SparseIR
         @testset "Type stability" begin
             # Integer grid
             int_grid = [0, 1, 2]
-            refined_int = SparseIR.refine_grid(int_grid, Val(2))
-            @test eltype(refined_int) === Float64
-            @test refined_int == [0.0, 0.5, 1.0, 1.5, 2.0]
+            refined = @inferred SparseIR.refine_grid(int_grid, Val(2))
+            @test eltype(refined) === Float64
+            @test refined == [0.0, 0.5, 1.0, 1.5, 2.0]
 
             # Float32 grid
             f32_grid = Float32[0, 1, 2]
-            refined_f32 = SparseIR.refine_grid(f32_grid, Val(2))
+            refined_f32 = @inferred SparseIR.refine_grid(f32_grid, Val(2))
             @test eltype(refined_f32) === Float32
             @test refined_f32 ≈ Float32[0, 0.5, 1, 1.5, 2]
         end
@@ -50,7 +50,11 @@ using SparseIR
             # Empty grid
             empty_grid = Float64[]
             @test isempty(SparseIR.refine_grid(empty_grid, Val(2)))
-
+            # Empty grid
+            empty_grid = Int[]
+            out_grid = SparseIR.refine_grid(empty_grid, Val(2))
+            @test isempty(out_grid)
+            @test eltype(out_grid) === Float64
             # Single point
             single_point = [1.0]
             @test SparseIR.refine_grid(single_point, Val(2)) == [1.0]