JTransforms 2.3

JTransforms is a free and open source, multithreaded FFT library written in pure Java.
Currently, four types of transforms are available: Discrete Fourier Transform (DFT), Discrete Cosine Transform (DCT), Discrete Sine Transform (DST) and Discrete Hartley Transform (DHT).
NOTE: JTransforms is licensed and distributed under the terms of the GNU General Public License (GPL), GNU Library or Lesser General Public License (LGPL) and Mozilla Public License 1.1 (MPL 1.1).

Main features:
- The fastest implementation of DFT, DCT, DST and DHT in pure Java (see benchmark).
- 1, 2 and 3 dimensional transforms.
- Arbitrary size of the data.
- Single and double precision.
- One-dimensional and multi-dimensional variants of 2D and 3D transforms.
- Automatic multithreading - threads are used automatically if #CPUs > 1.
- Optimized FFTs for real input data (40% faster than complex).

System requirements:
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Version restrictions:
- 1D transforms for not power-of-two sizes are sequential (when the mixed-radix is used).
- 1D transforms for power-of-two sizes can use only 2 or 4 threads.
- The number of threads must be a power-of-two number.
- Only in-place transforms are available.
- Only DCT-II and DCT-III are available.
- Only DST-II and DST-III are available.
- Only real DHT is available.

Enhancements
- Performance improvements for 3D FFT (realForwardFull() and realInverseFull() for not power-of-two sizes).
- Cosmetic changes.