Merge pull request #480 from N5N3/fix

Fix inference on `symmatrix` (patch for #472)

src/b-splines/indexing.jl

@@ -201,10 +201,8 @@ symmatrix(h::NTuple{1,Any}) = SMatrix{1,1}(h)
 symmatrix(h::NTuple{3,Any}) = SMatrix{2,2}((h[1], h[2], h[2], h[3]))
 symmatrix(h::NTuple{6,Any}) = SMatrix{3,3}((h[1], h[2], h[3], h[2], h[4], h[5], h[3], h[5], h[6]))
 function symmatrix(h::NTuple{L,Any}) where L
- @noinline incommensurate(N,L) = error("$L must be equal to N*(N+1)/2 (N = $N)")
- N = floor(Int, (2L)^(1//2))
- (N*(N+1))÷2 == L || incommensurate(N,L)
- l = Matrix{Int}(undef, N, N)
+ N = symsize(Val(L))
+ l = MMatrix{N,N,Int}(undef)
  l[:,1] = 1:N
  idx = N
  for j = 2:N, i = 1:N
@@ -221,3 +219,10 @@ function symmatrix(h::NTuple{L,Any}) where L
  SMatrix{N,N}(h[i] for i in l)
  end
 end
+
+# Use @generated to force const propagation
+@generated function symsize(::Val{L}) where L
+ N = floor(Int, sqrt(2L))
+ (N*(N+1))÷2 == L || error("$L must be equal to N*(N+1)/2 (N = $N)")
+ return :($N)
+end

test/issues/runtests.jl

@@ -155,10 +155,16 @@ using Interpolations, Test, ForwardDiff
  @test ForwardDiff.gradient(itp_test, [3.0, 2.0]) ≈ Interpolations.gradient(itp, 3.0, 2.0)
  end
  @testset "issue 469" begin
- dims = VERSION > v"1.7" ? 7 : 3 # symmatrix is unstable before 1.7, (^ was llvm based)
- A = zeros(Float64, ntuple(_ -> 5, dims))
- itp = interpolate(A, BSpline(Quadratic(Reflect(OnCell()))))
- @test (@inferred Interpolations.hessian(itp, ntuple(_ -> 1.0, dims)...)) == zeros(dims,dims)
+ # We have different inference result on different version.
+ max_dim = VERSION < v"1.3" ? 3 : isdefined(Base, :Any32) ? 7 : 5
+ for dims in 3:max_dim
+ A = zeros(Float64, ntuple(_ -> 5, dims))
+ itp = interpolate(A, BSpline(Quadratic(Reflect(OnCell()))))
+ @test (@inferred Interpolations.hessian(itp, ntuple(_ -> 1.0, dims)...)) == zeros(dims,dims)
+ end
+ @test Interpolations.symsize(Val(36)) == 8
+ @test Interpolations.symsize(Val(45)) == 9
+ @test_throws ErrorException Interpolations.symsize(Val(2))
+ @test_throws ErrorException Interpolations.symsize(Val(33))
  end
-
 end