A new package 'nnls' is now available on CRAN. The package provides an R interface to the Lawson-Hanson NNLS algorithm for non-negative least squares that solves the least squares problem A x b with the constraint x >= 0. The Lawson-Hanson NNLS algorithm was published in Lawson CL, Hanson RJ (1974). Solving Least Squares Problems. Prentice Hall, Englewood Cliffs, NJ. Lawson CL, Hanson RJ (1995). Solving Least Squares Problems. Classics in Applied Mathematics. SIAM, Philadelphia. and is available as Fortran77 code on Netlib (file lawson-hanson/all). The 'nnls' package interfaces to this code. Included in the examples section of the function 'nnls' is a test problem comparing NNLS to the L-BFGS-B method of 'optim' and to the 'solve.QP' function of the package 'quadprog'. NNLS is shown to be faster and slightly more accurate than these more general purpose algorithms for the test problem examined. I do not have access to S-PLUS or the S-PLUS source, but the help page for the S-SPLUS function 'nnls.fit' references Lawson and Hanson (1974), and is probably close to the port here. I have not written any methods for printing or summaries, and only return the solution x. On request, I can modify this behavior. I would be interested in suggestions, bug reports, and other comments. Kate Mullen ---- Katharine Mullen mail: Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, de Boelelaan 1081 1081 HV Amsterdam, The Netherlands room: T.1.06 tel: +31 205987870 fax: +31 205987992 e-mail: kate at nat.vu.nl homepage: http://www.nat.vu.nl/~kate/ _______________________________________________ R-packages mailing list R-packages at r-project.org https://stat.ethz.ch/mailman/listinfo/r-packages