Changes in Version 1.1-6

  o Load the "lattice" package in the vignettes in preparation to changes
    in the "flexmix" package.


Changes in Version 1.1-5

  o Conditional registration of effect() and allEffects() methods when "effects"
    package is loaded.


Changes in Version 1.1-4

  o Added a new function mptmix() for MPT mixture models, also known as
    latent-class MPT models. The design follows that of raschmix() and
    btmix(). Internally, the flexmix driver FLXMCmpt() is called to fit the
    finite mixture model. The function has not yet been fully tested and
    may change in future versions.


Changes in Version 1.1-3

  o Updated the example for btmix.


Changes in Version 1.1-2

  o The manuscript "Rasch Mixture Models for DIF Detection: A Comparison
    of Old and New Score Specifications." has now been published in
    Educational and Psychological Measurement, 75(2), 208-234.
    doi:10.1177/0013164414536183. A preprint version is included as
    vignette("scores", package = "psychomix").

  o Improved functionality for raschmix() to allow for item response
    data in the itemresp-class.

  o Improved axis labeling in plot function for raschmix objects.

  o In the plot method nchar(..., type = "width") is now used to determine
    the default abbreviation.
  
  o If suggested packages are needed internally, these are only called
    with :: semantics and not require()d anymore.
  

Changes in Version 1.1-1

  o Adapted raschmix() to work with both the old psychotools version
    0.2-0 and the new 0.3-0.
    
  o Updated the "scores" vignette which is now also accepted for publication
    in Educational and Psychological Measurement.


Changes in Version 1.1-0

  o Improved functionality for raschmix() to allow for differences 
    between components in terms of identified parameters.

  o Improved function raschmix() to leverage new functionality from 
    the flexmix package: Parameter estimates from the previous M-step 
    can now be used for initialization.

  o Function raschmix() can now model the score distribution to be 
    equal across all components (for both a "saturated" and a "meanvar" 
    specification of the score model).


Changes in Version 1.0-0

  o Official first stable release of the raschmix() functionality in the
    package, accompanying the manuscript "Flexible Rasch Mixture Models
    with Package psychomix" by Frick, Strobl, Leisch, and Zeileis,
    published in the Journal of Statistical Software 48(7). See
    citation("psychomix") for details.


Changes in Version 0.2-1

  o For increased numerical stability the default minprior control
    parameter in raschmix() is now 0.05 (as in flexmix) and not 0
    (as in the previous psychomix version).

  o Revised vignette("raschmix", package = "psychomix"). Specifically,
    there is a discussion of how the FLXMCrasch() can be used directly
    with flexmix() or stepFlexmix() from the "flexmix" package.

  o Improved function simRaschmix() to allow for a flexible specification
    of the data generating process. 
    
  o Added an effectsplot() function that leverages the "effects" package
    for visualizing the effects of the concomitant variables (if any) in
    the mixture model. This has not yet been fully tested and may change
    in future versions.
    
  o Added a new function btmix() for Bradley-Terry mixture models. The
    design follows that of raschmix() rather closely. Based on btReg.fit()
    from package "psychotools", there is a flexmix driver called FLXMCbtreg().
    The btmix() function is a convenience interface calling stepFlexmix()
    with the FLXMCbtreg() driver. This has not yet been fully tested and
    may change in future versions.


Changes in Version 0.1-1

  o First CRAN release of new "psychomix" package for fitting
    psychometric mixture models based on flexmix infrastructure. At the
    moment only Rasch mixture models are implemented in various flavors:
    with/without concomitant variables, different parametrizations
    of the score distribution (saturated vs. mean/variance specification).
    See vignette("raschmix", package = "psychomix") for details.

