COPYRIGHTS

This package includes and adapts third-party code for nearest-neighbour
search and Twinning-based subset selection. The BKP package as a whole is
licensed under GPL (>= 3). The third-party components listed below retain
their original copyright notices and license terms.

1. nanoflann
------------

File:
  inst/include/nanoflann.hpp

Copyright:
  Copyright 2008-2009 Marius Muja
  Copyright 2008-2009 David G. Lowe
  Copyright 2011-2022 Jose Luis Blanco

License:
  BSD license, as stated in the header of inst/include/nanoflann.hpp.

Use in this package:
  The nanoflann header is redistributed as part of this package to support
  kd-tree nearest-neighbour search used by the TwinBKP and TwinDKP routines.

Notes:
  The original copyright notice and BSD license text are retained in
  inst/include/nanoflann.hpp.


2. Twinning code adapted from twingp
-----------------------------------

File:
  src/twinning_bkp.cpp

Original source:
  The implementation is adapted from src/twinning.cpp in the twingp package,
  developed by Akhil Vakayil and V. Roshan Joseph.

Original copyright and license:
  Copyright 2023 Akhil Vakayil, as stated in the original source file.
  Apache License, Version 2.0.

Modifications in this package:
  The original Twinning implementation has been modified for the BKP package.
  In particular, the modified version separates the matrix used for global
  subset selection from the normalized input matrix, uses the normalized input
  matrix to compute the empirical covering radius, removes validation-index
  construction specific to TwinGP, and returns R-facing indices using
  one-based indexing.

Use in this package:
  The adapted code supports the global-subset selection step used by the
  TwinBKP and TwinDKP routines.

Notes:
  The original Apache-2.0 copyright notice is retained in the source file.
  The modifications are distributed as part of the BKP package under GPL
  (>= 3), which is compatible with Apache License 2.0 for this use.
