remove SIMD.jl

[fredrikekre]

Probably not needed with llvm6 and SLP vectorization enabled by default.

[codecov-io]

Codecov Report

Merging #93 into master will decrease coverage by 0.26%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #93      +/-   ##
==========================================
- Coverage   98.01%   97.74%   -0.27%     
==========================================
  Files          15       15              
  Lines         755      755              
==========================================
- Hits          740      738       -2     
- Misses         15       17       +2

Impacted Files	Coverage Δ
src/Tensors.jl	100% <ø> (ø)	⬆️
src/eigen.jl	86.66% <0%> (-1.67%)	⬇️

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[KristofferC]

No explicit SIMD:

julia> a = rand(Tensor{4,3});

julia> @which a ⊡ a
dcontract(S1::FourthOrderTensor{dim}, S2::FourthOrderTensor{dim}) where dim
     @ Tensors ~/.julia/dev/Tensors/src/tensor_products.jl:139

julia> @btime $a ⊡ $a;
  80.764 ns (0 allocations: 0 bytes)

Explicit SIMD:

julia> @which a ⊡ a
dcontract(S1::Tensor{4, 3, T}, S2::Tensor{4, 3, T}) where T<:Union{Float16, Float32, Float64}
     @ Tensors ~/.julia/dev/Tensors/src/simd.jl:279

julia> @btime $a ⊡ $a;
  58.187 ns (0 allocations: 0 bytes)