Initial implementation of SVE optimisations for ARM processors.

CHANGELOG.md

cmake/NektarSIMD.cmake

docs/developer-guide/library/LibUtilities/simdlib.tex

library/LibUtilities/SimdLib/allocator.hpp

library/LibUtilities/SimdLib/avx2.hpp

library/LibUtilities/SimdLib/avx512.hpp

library/LibUtilities/SimdLib/scalar.hpp

library/LibUtilities/SimdLib/sse2.hpp

library/LibUtilities/SimdLib/sve.hpp

library/LibUtilities/SimdLib/tinysimd.hpp

library/LibUtilities/SimdLib/traits.hpp

library/UnitTests/SIMD/CMakeLists.txt

library/UnitTests/SIMD/TestSimdLib.cpp