Disallow mixing offset and non-offset axes in conv input

ext/OffsetArraysExt.jl

@@ -2,6 +2,6 @@ module OffsetArraysExt
 import DSP
 import OffsetArrays
 
-DSP.conv_with_offset(::OffsetArrays.IdOffsetRange) = true
+DSP.conv_axis_with_offset(::OffsetArrays.IdOffsetRange) = true
 
 end

src/dspbase.jl

@@ -660,8 +660,16 @@ function _conv_td!(out, output_indices, u::AbstractArray{<:Number, N}, v::Abstra
 end
 
 # whether the given axis are to be considered to carry an offset for `conv!` and `conv`
-conv_with_offset(::Base.OneTo) = false
-conv_with_offset(a::Any) = throw(ArgumentError("unsupported axis type $(typeof(a))"))
+conv_axis_with_offset(::Base.OneTo) = false
+conv_axis_with_offset(a::Any) = throw(ArgumentError("unsupported axis type $(typeof(a))"))
+
+function conv_axes_with_offset(as::Tuple...)
+    with_offset = ((map(a -> map(conv_axis_with_offset, a), as)...)...,)
+    if !allequal(with_offset)
+        throw(ArgumentError("cannot mix offset and non-offset axes"))
+    end
+    return first(with_offset)
+end
 
 const FFTTypes = Union{Float32, Float64, ComplexF32, ComplexF64}
 
@@ -704,12 +712,8 @@ function conv!(
     v::AbstractArray{<:Number, N};
     algorithm=:auto
 ) where {T<:Number, N}
+    offset = conv_axes_with_offset(axes(out), axes(u), axes(v)) ? 0 : 1
     output_indices = CartesianIndices(map(axes(out), axes(u), axes(v)) do ao, au, av
-        input_has_offset = conv_with_offset(au) || conv_with_offset(av)
-        if input_has_offset !== conv_with_offset(ao)
-            throw(ArgumentError("output must have offset axes if and only if the input has"))
-        end
-        offset = input_has_offset ? 0 : 1
         return (first(au)+first(av) : last(au)+last(av)) .- offset
     end)
 
@@ -752,9 +756,13 @@ function conv!(
     end
 end
 
-conv_output_axis(au, av) =
-    conv_with_offset(au) || conv_with_offset(av) ?
-    (first(au)+first(av):last(au)+last(av)) : Base.OneTo(last(au) + last(av) - 1)
+function conv_output_axes(au::Tuple, av::Tuple)
+    if conv_axes_with_offset(au, av)
+        return map((au, av) -> first(au)+first(av):last(au)+last(av), au, av)
+    else
+        return map((au, av) -> Base.OneTo(last(au) + last(av) - 1), au, av)
+    end
+end
 
 """
     conv(u, v; algorithm)
@@ -768,7 +776,7 @@ function conv(
     u::AbstractArray{Tu, N}, v::AbstractArray{Tv, N};  kwargs...
 ) where {Tu<:Number, Tv<:Number, N}
     T = promote_type(Tu, Tv)
-    out_axes = map(conv_output_axis, axes(u), axes(v))
+    out_axes = conv_output_axes(axes(u), axes(v))
     out = similar(u, T, out_axes)
     return conv!(out, u, v; kwargs...)
 end
@@ -792,7 +800,7 @@ Uses 2-D FFT algorithm.
 """
 function conv(u::AbstractVector{T}, v::Transpose{T,<:AbstractVector}, A::AbstractMatrix{T}) where T
     # Arbitrary indexing offsets not implemented
-    if any(conv_with_offset, (axes(u)..., axes(v)..., axes(A)...))
+    if any(conv_axis_with_offset, (axes(u)..., axes(v)..., axes(A)...))
         throw(ArgumentError("offset axes not supported"))
     end
     m = length(u)+size(A,1)-1

test/dsp.jl

@@ -72,10 +72,12 @@ end
 
         offset_arr = OffsetVector{Int}(undef, -1:2)
         offset_arr[:] = a
-        @test conv(offset_arr, 1:3) == OffsetVector(expectation, 0:5)
+        @test_throws ArgumentError conv(offset_arr, 1:3)
+        @test conv(offset_arr, OffsetArray(1:3)) == OffsetVector(expectation, 0:5)
         offset_arr_f = OffsetVector{Float64}(undef, -1:2)
         offset_arr_f[:] = fa
-        @test conv(offset_arr_f, 1:3) ≈ OffsetVector(fexp, 0:5)
+        @test_throws ArgumentError conv(offset_arr_f, 1:3)
+        @test conv(offset_arr_f, OffsetArray(1:3)) ≈ OffsetVector(fexp, 0:5)
         @test_throws ArgumentError conv!(zeros(6), offset_arr, 1:3) # output needs to be OA, too
         @test_throws ArgumentError conv!(OffsetVector{Int}(undef, 1:6), 1:4, 1:3) # output mustn't be OA
 
@@ -156,7 +158,8 @@ end
 
         offset_arr = OffsetMatrix{Int}(undef, -1:1, -1:1)
         offset_arr[:] = a
-        @test conv(offset_arr, b) == OffsetArray(expectation, 0:3, 0:3)
+        @test_throws ArgumentError conv(offset_arr, b)
+        @test conv(offset_arr, OffsetArray(b)) == OffsetArray(expectation, 0:3, 0:3)
 
         for (M1, M2) in [(10, 20), (190, 200)], (N1, N2) in [(20, 10), (210, 200)], T in [Float64, ComplexF64]
             u = rand(T, M1, M2)