----------------------------------------------------------------

	CHANGES IN transport VERSION 0.12-2  (2020-03-11)

OVERVIEW

    o  We thank Christoph Weitkamp for contributions.

    o  Fixes a serious bug in the main transport function.
       For method = "networkflow" and mass vectors a, b
       containing zeroes, the results were typically wrong before.

    o  Function transport_track now uses argument fps (frames
       per second) instead of delay.time for generation of
       animated gifs. This argument is used consistently. 

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.12-1  (2019-08-07)

OVERVIEW

    o  Fixes a compilation error under Solaris.

    o  Returns to using a Makevars file instead of the
       configure script for the same openmp functionality
       as in the previous version.

    o  We thank Brian Ripley for pertinent hints on both. 


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.12-0  (2019-08-05)

OVERVIEW

    o  We thank Nicolas Bonneel for contributions.

    o  The main workhorse function transport has a new method
       "networkflow". This is currently the recommended method for
       solving the discrete optimal transport problems directly
       via a simplex algorithm (it is fastest unless special
       structure is known, e.g. p=2).
       The method is available for objects of classes pp, wpp,
       pgrid. The code is based on the modified version of
       the Lemon Library provided by Nicolas Bonneel.
       https://github.com/nbonneel/network_simplex
       
    o  A new configure script checks for openmp support at install time.
       If supported the installed version allows the user to run a
       multithreaded version of the "networkflow" method via a new
       argument "threads" in the appropriate transport functions.
       
    o  Fixes a bug in the transport.track function which could cause
       an error when trying to generate a gif using this function.
       Also adds some minor customization options to this function.
 

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.11-2  (2019-06-12)

OVERVIEW

    o  We thank Luc Lehericy for contributions.

    o  A bug in the function transport.wpp was fixed which
       for strongly unbalanced weights created sometimes
       an infinite loop.
 

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.11-1  (2019-04-17)

OVERVIEW

    o  We thank Samuel Ackerman for contributions.

    o  The functions subwasserstein and transport.pp are
       faster now. Depending on the example the speed increase
       can be very substantial.      

SIGNIFICANT CHANGES

    o  Function subwasserstein is much faster now for large objects
       because distance matrixes are not precomputed anymore. Set
       the new argument precompute=TRUE if you must reproduce the
       old behaviour.       

BUG FIXES

    o  Due to the misplacement of a line of code, epsilon-scaling
       in the auction algorithm was not working properly for the
       function transport.pp. In some simple pathological examples
       the algorithm took very long. Reported by Samuel Ackerman.
       Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.11-0  (2019-02-03)

OVERVIEW

    o  Several improvements regarding exact and approximate
       computations of Wasserstein distances, including a
       bug fix.       

NEW FUNCTIONS
    
    o  subwasserstein
    Allow for approximate computation of Wasserstein distances
    via subsampling. Code by Jörn Schrieber

SIGNIFICANT CHANGES

    o  Function wasserstein can now also compute Wasserstein
       distances in the vanilla case of two mass vectors with
       cost matrix.

BUG FIXES

    o  The result was incorrectly normed when applying function
       wasserstein to objects of class "wpp" with prob=TRUE. Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.10-0  (2018-12-24)

OVERVIEW

    o  Semidiscrete optimal transport can now also be
       computed for p=1 (in addition to p=2) if CGAL is
       available. Adapt then src/Makevars and install this
       package from source. This functionality is based on
       stand-alone C++ code by Valentin Hartmann
       
    o  Easier extraction of the Wasserstein distance
       from semidiscrete optimal transport results

NEW FUNCTIONS
    
    o  semidiscrete1
    The workhorse function for computing semidiscrete
    optimal transport for p=1. This is called by the
    function transport (if first input object has class
    pgrid, second input object has class wpp and p=1) and
    by the function semidiscrete (if p=1).
    Calling semidiscrete1 directly offers finer control
    of the algorithm.

    o  plot_apollonius
    The workhorse function for plotting the semidiscrete
    optimal transport plan for p=1. This is called by the
    function plot.pgrid (if the second input object has
    class wpp and p=1).
    Calling plot_apollonius directly allows to plot
    arbitrary Apollonius diagrams (a.k.a. weighted Voronoi
    tesselations) based on a two-column matrix of centers
    and a vector of weights. It allows offers finer
    control over plotting.


SIGNIFICANT CHANGES

    o  Functions transport and plot.pgrid can now compute
       and plot semidiscrete optimal transport plans also
       for p=1 (in addition to p=2) using an object of class
       pgrid and an object of class wpp. The result of the
       plot is an Apollonius diagram (a.k.a. weighted
       Voronoi tesselations) consisting of hyperbola
       segments.

    o  The object returned by semidiscrete now always contains
       a component giving the Wasserstein distance between the
       input objects. The function wasserstein simply extracts
       this component.

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.9-4  (2017-10-03)

OVERVIEW

    o  Compilation with the most recent version of clang resulted in
       an error. Fixed.

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.9-3  (2017-09-29)

OVERVIEW

    o  Minor change to remove a compiler warning    

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.9-2  (2017-09-28)

OVERVIEW

    o  Minor changes in Makevars to enable compilation under Windows and
       pass CRAN checks     

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.9-1  (2017-09-15)

OVERVIEW

    o  Minor bug fixes     

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.9-0  (2017-08-24)

OVERVIEW

    o  Fixed serious bug, introduced in version 0.7-0,
       by which the algorithm hanged for pgrid-objects if p>1
       method="revsimplex" (the default) if masses are not integer valued    

    o  New method "shielding" for pgrid-objects if p=2 that is considerably
       faster than the existing methods. Option to link package
       against CPLEX makes this combination even much faster and enables
       computation for 128x128 grids within a few seconds.
       C++ code by Bernhard Schmitzer 

----------------------------------------------------------------

	CHANGES IN transport VERSION 0.8-2  (2017-03-09)

OVERVIEW

    o  New function wasserstein1d to compute the Wasserstein
       distance between two univariate samples (with weights)


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.8-1  (2016-12-03)

OVERVIEW

    o  We thank Atreju Tauschinsky for contributions

    o  The wasserstein function supports now the wpp class

    o  Several minor bug fixes


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.8-0  (2016-10-15)

OVERVIEW

    o  We thank Florian Heinemann and Timo Wilm for contributions

    o  New class weighted point patterns with full functionality

    o  Optimal transport between pgrid and wpp that returns 
       transport tesselation

    o  Dynamic optimal transport (displacement interpolation)

NEW CLASSES

    o  wpp
    The class wpp describes general discrete measures with
    finite support, i.e. patterns of finitely many "weighted"
    points (without specific structure for the locations or
    weights). There are constructors for this class,
    as well as plot, print and summary functions. The
    function 'transport' can deal with this class.
    We thank Timo Wilm for help with creating this class.
    
NEW FUNCTIONS
    
    o  semidiscrete
    Computes the transport map (in the form of a power
    diagram) for the semidiscrete transport problem
    from a pgrid to a wpp object for the case p=2.
    This function is not usually called by the user
    because the function transport offers the same
    flexibility now.

    o  plot_pgrid_wpp
    Plots a representation of a transport map (available
    as a power diagram) between a pgrid and a wpp object.
    This function gets called when using the generic plot
    function with a pgrid and a wpp object (in that order),
    but a direct call to plot_pgrid_wpp by the user offers
    more possibilites for customizing the plot.

    o  transport_track
    Computes a dynamic version of a given transference plan
    by interpolating in time. The linear interpolation of
    the projections of the transference plan is computed,
    which in many important cases corresponds to the
    displacement interpolation. The result can be either
    returned as an array or is saved as an animated gif.
    We thank Florian Heinemann for contributing large
    parts of this function.

SIGNIFICANT CHANGES

    o  transport
    Can now deal with two wpp objects and in the case p=2
    also with one pgrid and one wpp object as inputs
    (in that order).

    o  aha
    It is now possible to return the parameters for the optimal
    power diagram, rather than the (approximative) optimal transference
    plan in terms of the pixel centers of the source measure. For
    this, use the new option powerdiag.

OTHER USER-VISIBLE CHANGES

    o  pgrid
    If no information is provided on the positions of the pixels, it is
    now assumed that we have square pixels and the boundary points
    in the first dimension are 0 and 1 (previous behaviour: boundary
    points in every dimension are 0 and 1, leading to non-square pixels
    if the pgrid is non-square).

    o  pgrid
    A pgrid object has two additional components 'totmass' giving
    the sum of pixel values, and 'totcontmass' giving the sum of
    pixel values divided by pixel areas. The former may be interpreted
    as totol mass of pgrid if interpreted as a discrete measure on the
    grid of pixel centers. The latter may be interpreted as total
    mass of pgrid if interpreted as a continuous measure with constant
    density on each pixel (seen as small contiguous rectangles).

BUG FIXES

    Various smaller bug fixes for special input.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.7-5  (2016-09-28)

OVERVIEW

    o  We thank Ramon Diaz-Uriarte for contributions

    o  aha can return optimal power diagram now

    o  Several minor bug fixes

SIGNIFICANT CHANGES

    o  aha
    It is now possible to return the parameters for the optimal
    power diagram, rather than the (approximative) optimal transference
    plan in terms of the pixel centers of the source measure. For
    this, use the new option powerdiag.

BUG FIXES

    o  transport.pp, transport.default
    Computing the optimal transport from a mass distribution
    to itself resulted in an error.
    Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.7-4  (2016-06-28)

OVERVIEW

    o  We thank Yann Abraham and Stefan Kain for contributions

    o  Several unnecessary outputs are now suppressed by default
       (timing information, warnings about degenerate bases that 
       did not affect the result)

    o  Several minor bug fixes

BUG FIXES

    o  transport.pgrid
    For p=1 computing the optimal transport from a mass distribution
    to itself resulted in a segfault or an error (depending on the
    method used).
    Fixed.

    o  transport.pgrid
    Having a mass distribution of integers and at least one zero could
    cause an integer overflow.
    Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.7-3  (2016-02-24)

OVERVIEW

    o  We thank Ludo Daemen and Stefan Kain for contributions

    o  Minor changes in the documentation and a bug fix

BUG FIXES

    o  transport.default
    Using transport.default with the shortlist method gave an error
    message if no shortlist parameters were set.
    Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.7-0  (2015-10-21)

OVERVIEW

    o  There are two new ways for computing starting solutions
    in transport.default and transport.pgrid with
    method="revsimplex", which lead to substantial speed
    improvements (mainly in transport.pgrid)
       
    o  Several minor bugfixes

SIGNIFICANT CHANGES

    o  transport.pgrid, transport.default
    When method="revsimplex" is chosen, transport.pgrid can now
    start from a solution that is based on the optimal transport
    between two coarsened problems. This "multiscale" behaviour is invoked
    automatically if p>1, the grid is 2-dimensional, of a certain
    minimal size, and has an even number of vertices in each direction
    (for p=1 use the control parameter nscales as in previous
    versions). Both transport.pgrid and transport.default can also
    be started from a solution based on the "Modified Row Minimum
    Rule" (newly implemented in C Code). This is the default
    behaviour now for transport.default, and also for transport.pgrid
    if the multiscale starting solution described above cannot
    be computed.

    To get the behaviour of older versions, say
    control=list(start="nwcorner") in the transport function.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.6-3  (2014-10-16)

OVERVIEW

    o  Minor changes in the documentation


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.6-2  (2014-06-21)

OVERVIEW

    o  Minor changes in the documentation and a bug fix

BUG FIXES

    o  aha
    In the underlying C code integer overflows were possible (usually
    without noticable effects on the result).
    Fixed.


----------------------------------------------------------------

	CHANGES IN transport VERSION 0.6-1  (2014-05-30)

OVERVIEW

    o  First public release
