NEWS.md

In SAM: Sparse Additive Modelling

SAM Changelog

v1.3

Bug Fixes

• Fixed KKT validation: inactive groups are now checked after every Level 1 iteration, not only when not converged.
• Fixed grpSVM ya_idx active-set logic that only checked the first element of each group instead of all p coefficients.
• Replaced assert() with runtime error checks in grplasso, grpLR, and grpPR (asserts are compiled out under -DNDEBUG).
• Added NULL checks for all malloc calls in grpSVM.

New Features

• dfmax parameter for early stopping when the number of non-zero groups exceeds a threshold (all four families).
• verbose parameter to print per-lambda iteration info.
• Deviance-ratio and deviance-change early stopping (dev.ratio.thr, dev.change.thr) for samQL, samLL, and samEL.
• Unified sam() entry point dispatching by family argument (R and Python).
• coef() S3 methods for all four model classes.
• solver = "actgd" option for samQL (group active gradient descent with strong-rule screening, L1 only).
• type.gaussian option for samQL ("naive" / "covariance" / "auto").
• runtime field on fitted objects (R: $runtime, Python: .runtime_seconds).

Python Wrapper

• New pysam-sam Python package calling the same C++ core via ctypes.
• Pure-Python spline basis (no R dependency at runtime).
• Full API parity: samLL, samHL, samEL, samQL + predict functions.

Performance

• Cached wXX products and no-op update_auxiliary for linear objective.
• C API deduplication via c_api_utils.h.

Code Quality

• Removed redundant fit$nkots field from R wrappers.
• Removed unused fit$XX (full design matrix) from samQL output.
• Removed unused V(d) declarations in grpLR and grpPR.
• Extracted shared .sam_print_path() / .sam_plot_path() helpers.
• Removed unused scipy dependency from Python package.
• Fixed legacy PICASSO_SOLVER_PARAMS_H header guard.
• Added root .gitignore.
• Added test coverage for samHL and samEL.

v1.2

• Initial CRAN release with samQL, samLL, samEL, samHL.

SAM documentation built on March 13, 2026, 9:08 a.m.