Changes in version 0.5.1 (2023-05-05)                  

    o   Fixed incorrect use of data_file() functions in the
	documentation, pointed out by Michael Lai.

                  Changes in version 0.5 (2021-09-19)                   

    o   Added function data_matrix() to support data from a sparse
	matrix object in R, contributed by David Cortes (@david-cortes,
	#17).

    o   Fixed the different result on macOS.

                 Changes in version 0.4.5 (2021-05-14)                  

    o   Fixed the dependence on rmarkdown, thanks to Kurt Hornik.

                 Changes in version 0.4.4 (2021-01-10)                  

    o   Fixed the problem that recosystem gives different results on
	Windows compared with other OS, reported by Prof. Michael
	Trusov.

                 Changes in version 0.4.3 (2020-05-18)                  

    o   Updated LIBMF to the newest version (403153c) in the upstream
	repository.

    o   Fixed a logical operation bug and a virtual destructor bug
	detected by CRAN.

                 Changes in version 0.4.2 (2017-09-02)                  

    o   Added the missing "nbin" parameter in $train() and $tune().
	(#6, reported by @Tutuchan).

    o   Added a progress bar for model tuning, controlled by the
	"progress" parameter in $tune().  (#5, suggested by @talegari).

                 Changes in version 0.4.1 (2017-03-21)                  

    o   Fixed the misleading column name "rmse" in the return value of
	$tune().

    o   Also updated the documentation accordingly.

    o   Fixed the wrong parameter name in .Call(), thanks to Kurt
	Hornik.

    o   Now using the prettydoc package to format vignettes.

                  Changes in version 0.4 (2016-07-13)                   

    o   Updated LIBMF to version 2.01.

    o   API change from LIBMF 2.01:
	
	  • The cost option in $train() and $tune() has been expanded
	    to and replaced by costp_l1, costp_l2, costq_l1, and
	    costq_l2, to allow for more flexibility of the model.
	
	  • A new loss parameter in $train() and $tune() to specify
	    loss function.

    o   Other API change:
	
	  • Data input and output are now managed in a unified way via
	    functions data_file(), data_memory(), out_file(),
	    out_memory(), and out_nothing(). See ?data_source and
	    ?output_format for more information.
	
	  • As a result, a number of arguments in functions $tune(),
	    $train(), $output(), and $predict() now should be objects
	    returned by these input/output functions.

                  Changes in version 0.3 (2015-05-30)                   

    o   Updated LIBMF to version 1.2.

    o   Due to API change in LIBMF 1.2, $convert_train() and
	$convert_test() have been removed, and $train() and $predict()
	have changed API accordingly.

    o   New member function $tune() for tuning model parameters.

                 Changes in version 0.2.5 (2015-02-08)                  

    o   New member function $output() to output factorization matrices.

                 Changes in version 0.2.4 (2014-09-13)                  

    o   (Internal) Avoided using C RNG.

    o   Fixed UBSAN runtime errors, thanks to Prof. Brian Ripley.

                 Changes in version 0.2.3 (2014-09-11)                  

    o   (Internal) Using pthreads on Windows to support multithreading.

                        Changes in version 0.2.2                        

    o   (Internal) Using portable code to allocate aligned memory.

                 Changes in version 0.2.1 (2014-09-05)                  

    o   Rolled back to Rcpp due to a NOTE in R CMD check.

    o   Changed package name from Recosystem to recosystem.

    o   Now using R to generate random numbers in the algorithm, so the
	result is reproducible by setting seeds inside R.

                         Changes in version 0.2                         

    o   Now linking to Rcpp11.

    o   A new parameter verbose to control output information.

                         Changes in version 0.1                         

    o   Initial version.