All R code and documentation in this package is licensed under the terms of the GPL 
license -- see COPYING in the top level of the R directory tree for further details.  

All fortran and C code in the src directory, with the exception of cholesky.f is also
licensed on the GPL license, see

	http://www.cs.umn.edu/Research/arpa/SPARSKIT/sparskit.html

for explicit stipulation for sparskit.f.  The code in cholesky.f  is a modified version of
code originally written by Esmond Ng and Barry Peyton.  

The modified version is distributed as part of PCx by Czyzyk, Mehrotra, Wagner, 
and Wright and is copywrite by the University of Chicago.  The PCx distribution 
makes the following stipulation:


	This software discloses material protectable under copyright 
	laws of the United States. Permission is hereby granted to use, 
	reproduce, prepare derivative works, and redistribute to others 
	at no charge, provided that the original PCx copyright notice, 
	Government license and disclaimer are retained and any changes 
	are clearly documented; however, any entity desiring permission 
	to use this software within a commercial organization or to 
	incorporate this software or a work based on the software into 
	a product for sale must contact Paul Betten at the Industrial 
	Technology Development Center, Argonne National Laboratory.

		PAUL BETTEN
		betten@anl.gov
		Industrial Technology Development Center,
		Argonne National Laboratory,
		Argonne, IL 60439
		(630) 252-4962
		FAX: (630) 252-5230 

It should be stressed that cholesky.f was NOT written by the authors of PCx, it
was only incorporated and distributed by them.  My personal take on this is
described in a message written to R-devel in early September, 2009.

   Comrades,
   
   When talk turns to the purity of the revolution, and purge of packages then
   the guillotine can't be far behind.  We all remember Lenin berating the
   "renegade Kautsky" for his "pragmatism," and we know where that led...
   
   So let me put in a good word for pragmatism, and incidentally for saving one of my 
   own packages, SparseM, and perhaps eventually my neck.  Last week Kurt asked
   me to look into a SparseM licensing quirk based on an inquiry from the Fedora
   folks.  SparseM is GPL except for one routine cholesky.f written at Oakridge
   Lab by E. Ng and B. Peyton.  Our version of the code was redistributed in the
   package PCx which was copywrited by the U. of Chicago, who specified that
   commercial users should contact someone at Argonne National Lab.  Since the
   beginning we have retained this language in the License file of SparseM, even
   though the code in question was not actually developed as a part of PCx.
   
   I contacted one of the original PCx developers who responded as follows:
   
   	The routine you mention was distributed with PCx but not part 
   	of it as you see from the legalese and not covered by the PCx 
   	copyright.  I tried to interest the authors of that code 
   	in legal issues in around 1997 but could not get them 
   	motivated (frankly I also can't get too interested).
   
   To which I heartily concurred.  If someone who is worried about getting sued
   would like to dig into this can of worms, then fine.  But life is too short
   for the rest of us.  This is quite a murky business, we shouldn't create 
   incentives to make it murkier by covering up relevant language on licensing.
   But surely we can also all agree that CRAN has been a fantastic success, and
   adding new constraints on its operation is ill-advised.
   
   Roger Koenker

   PS [Added August, 2010]  Nervous Nellies expecting to get rich with comercialization
   of R code and needing sparse matrices are advised to consider the package Matrix.
   I would make this switch myself if I had time and energy to recode the applications
   in quantreg that rely on SparseM.

   PS  [Added November, 2011]  Another inquiry by vigilantes from Google has prompted
   me to explore this further.  I would like to think that cholesky.f could be liberated
   from its current purgatory and promoted to the sacred realm of the GPL, but only
   time will tell.
