This is a list of API changes.
SLOPE, because the only two functions from SLOPE that are used in grpSLOPE are being deprecated and removed from SLOPE package versions newer than 0.1.3.SLOPE has been removed (see above), the two functions SLOPE::SLOPE_solver and SLOPE::prox_sorted_L1 (including the underlying C implementation) have been adapted from SLOPE version 0.1.3 into this version of the grpSLOPE package.proximalGradientSolverGroupSLOPE used by default within function grpSLOPE), an ADMM solver has been implemented for the Group SLOPE model (function admmSolverGroupSLOPE).Fix for the installation error on r-oldrel-windows-ix86+x86_64 (R v3.2.5) in the CRAN package check results. This error was caused by the generic S3 method sigma() not being available from the stats package prior to R v3.3.0.
Checks for missing data in the inputs X, y and group were added in grpSLOPE().
A check for whether the input matrix X has columns with 0 variance is performed in grpSLOPE() when normalize=TRUE. This should prevent division by 0, when the columns of X are standardized to have norms equal to 1.