This package contains mostly contains source code developed by DPAC,
the Gaia Data Processing and Analysis Consortium.

At present it contains:

ParallaxTools:
-------------

Code written by Enrique Utrilla (ESAC) for distance estimation
from parallax values and errors.  This is based on theoretical
work by Coryn Bailer-Jones and Tri Astraatmadja, as documented
Astraatmadja and Bailer-Jones, ApJ vol.833, p.119 (2016)
(2016ApJ...833..119A, DOI 10.3847/1538-4357/833/1/119).

The code was copied from the DPAC subversion repository
at https://gaia.esac.esa.int/dpacsvn; the initial import
is the contents of DPAC/CU9/software/ParallaxTools/java/src
at revision 598158.

The code has been modified slightly by Mark Taylor, so that
it can be used without dependency on any external libraries
(but see below).  The details of the changes can be found
by examinining the git history.

DPAC code (GaiaTools) is generally intended to be LGPL,
but in practice most of it is not because of some dependencies
on non-open-source code.  The DPAC source files in this
package were used by agreement with Uwe Lammers (ESAC),
by email on 22 Feb 2018:

   Date: Thu, 22 Feb 2018 16:02:10 +0000
   From: Uwe Lammers <ulammers@sciops.esa.int>
   Reply-To: uwe.lammers@sciops.esa.int
   To: Mark Taylor <m.b.taylor@bristol.ac.uk>, uwe.lammers@sciops.esa.int
   Subject: Re: ParallaxTools license

   Dear Mark,

   fantastic that you are building this into TOPCAT/STILTS!
   I see no problem with releasing the respective code together
   with TOPCAT under GPL.

   We have plans to open-source more Gaia s/w, notably GaiaTools
   but did not get to it yet. There is also still a licensing issue
   we need to sort out, viz. GT is LGPL but has some dependencies to
   code under GPL and such a constellation automatically triggers
   copyleft for the whole combo (as you probably know).

   Cheers
   Uwe

The original user documentation for this library is in DPAC
(LiveLink) document GAIA-C9-TN-ESAC-EUM-054.

uk.ac.starlink.dpac.math:
------------------------

Some supporting files required by the DPAC code.
At present this contains modified copies of three source files
from Apache commons-math3, as required for spline interpolation
by ParallaxTools.

These files were originally acquired from the repository
http://git-wip-us.apache.org/repos/asf/commons-math.git,
with tag MATH_3_6_1.  This code was originally licenced
under the Apache License Version 2.0.

Then, I just deleted those parts that referenced other
Apache classes so I could use it standalone.  Nothing
essential was lost.

uk.ac.starlink.dpac.epoch:
-------------------------

GaiaTools classes from gaia.cu1.tools for epoch transfomration,
acquired from the DPAC subversion repository at
https://gaia.esac.esa.int/dpacsvn; the initial import is of files:

    CU1/software/CrossMatch/src/gaia/cu1/tools/cu1crossmatch/epochtransformation/EpochTransformation.java
    CU1/software/GaiaTools/src/gaia/cu1/tools/numeric/algebra/GVector3d.java

at revision 579554.

The code has been modified so that these classes can be used without
external dependencies.  Since the signatures (e.g. implemented
interfaces) have been changed, the packages in which they live have
been changed to avoid problems if they are used on the same
classpath as original GaiaTools classes.  The details of the changes
can be found by examining the git history.  As for ParallaxTools,
this code is licensed under the LGPL.

