Changes in version 0.5.1 (2026-01-11) Minor changes - Replaced qpmadr::solveqp() with quadprog::solve.QP() because the {qpmadr} package was archived on CRAN as of 2026-01-10. Changes in version 0.5.0 (2025-10-05) Major changes - Simplified specification of group penalty via abclass.control(). Minor changes - Changed the default alignment to lambda for cv.abclass() and refit in et.abclass() if a sequence of lambda's is specified. A warning message would be thrown out for the former. Changes in version 0.4.0 (2022-09-18) New features - Added support of sparse matrix x of class sparseMatrix (provided by the {Matrix} package) for abclass() and predict.abclass(). - Added new functions named cv.abclass() and et.abclass() for training and tuning the angle-based classifiers with cross-validation and an efficient tuning procedure for lasso-type algorithms, respectively. See the corresponding function documentation for details. - Added experimental classifiers with sup-norm penalties. See the functions supclass() and cv.supclass() for details. Major Changes - Simplified the function abclass() and moved the tuning procedure by cross-validation to the function cv.abclass(). Minor Changes - Changed the default values of the following arguments for abclass.control(). - alpha: from 0.5 to 1.0 - epsilon: from 1e-3 to 1e-4 Bug fixes - Fixed alignment in abclass.control(). Changes in version 0.3.0 (2022-05-28) New features - Added experimental group-wise regularization by group SCAD and group MCP penalty. - Added a new function named abclass.control() to specify the control parameters and simplify the main function interface. Minor changes - Renamed the argument max_iter to maxit for abclass(). Bug fixes - Fixed the validation indices in the cross-validation procedure Changes in version 0.2.0 (2022-04-12) New features - Added experimental group-wise regularization by group lasso penalty. Minor changes - Removed the function call from the return of abclass() to avoid unnecessarily large returned objects - Changed the default value of lum_c for abclass() from 0 to 1. - Renamed the argument rel_tol to epsilon for abclass(). Bug fixes - Fixed the first derivatives of the boosting loss - Fixed the label prediction by using the fitted inner products instead of the probability estimates - Fixed the computation of regularization terms for verbose outputs in AbclassNet - Fixed the computation of validation accuracy in cross-validation - Fixed the assignment of lum_c in the associated header files. - Fixed the computation of lower bound for distinct observation weights Changes in version 0.1.0 (2022-03-07) New features - The first release of abclass providing the multi-category angle-based large-margin classifiers with various loss functions.