HPTT is a high-performance C++ library for out-of-place tensor
transpositions.

Key Features:
* Multi-threading support
* Explicit vectorization
* Auto-tuning (akin to FFTW)
  * Loop order
  * Parallelization
* Multi architecture support
  * Explicitly vectorized kernels for (AVX and ARM)
* Supports float, double, complex and double complex data types
* Supports both column-major and row-major data layouts

WWW: https://github.com/springer13/hptt