EVOLUTION-MANAGER

Edit File: Announce.txt

Basically the text of the R-packages posting on Mar 28, 2008 : https://stat.ethz.ch/pipermail/r-packages/2008/000911.html ------------------------------------------------------------------------ This weekend, a new version of "the Matrix" (well, actually the R package named "Matrix") will become available on the CRAN mirrors. As some of you have noticed, the version numbers (current is version 0.999375-8) are converging to one, and we feel that we have solved enough of the many (mostly small) problems to announce that release 1.0-0 is imminent. In the DESCRIPTION of the package we say -------------------------------------------------------------- Title: A Matrix package for R Author: Douglas Bates <....> and Martin Maechler <....> Maintainer: Doug and Martin <Matrix-authors@R-project.org> Description: Classes and methods for dense and sparse matrices and operations on them using Lapack, CSparse and CHOLMOD -------------------------------------------------------------- The Matrix package provides efficient methods for several formal (i.e. S4) classes of matrices where each of the actual classes are some combination of the following three categories 1) dense or sparse 2) symmmetric, triangular, diagonal or "general" (or "permutation") 3) numeric ("d"ouble), logical (TRUE/FALSE/NA) or "patter[n]" (0/1) matrices Interfaces to many efficient algorithms from Lapack (for "dense") and from CHOLMOD / Csparse (for "sparse") are all implemented via method definitions for the customary linear algebra functions %*%, t(), crossprod(), tcrossprod(), chol(), qr(), solve(), colSums(), rowSums(), kronecker(), determinant(), ... and for various formal groups of generics, such as "Math" (sin,exp,gamma,..) "Arith" (+,-,*,...), "Logic" (>, <=, ..), "Summary" (sum, max, ...) etc; is.na() Furthermore, 'indexing' : "A[...]" and "A[..] <- value" of all(!) kinds of S/R indexing and some new generic functions such as lu() {LU decomposition} Schur(), BunchKaufman(), norm(), rcond() {Matrix norms and condition numbers} expm() {Matrix exponential}, band(), triu(), tril() {extract band-diagonal or triangular sub-matrices} symmpart(), skewpart() { (x + t(x))/2 and (x - t(x)) / 2 } are provided. Further, an extension to the xtabs function xtabs(*, sparse=TRUE) for large sparse, two-way contingency tables and coercion of one *factor* (possibly crossed with one <numeric>) to the corresponding (potentially huge) sparse model matrix for sparse least squares and related computations. Further to the above, "Matrix" objects are also constructed by Matrix(), spMatrix(), bdiag() {block-diagonal}, Diagonal() and many as(., "....Matrix") possibilities. The Matrix package also provides a C level API (header files of exported C functions providing low-level functionality) to many of its internal algorithms that other packages can link to. Currently, the 'lme4' package makes heavy use of these exported C functions. --------------------------------------------------------------------------- One of the things we plan to improve considerably is the documentation for the package. Currently there are four vignettes but all but the Comparisons: Comparisons of Least Squares calculation speeds are really not complete in one way or another. --------------------------------------------------------------------------- We would appreciate current users of the Matrix package (and also generally interested useRs) exploring the package's capabilities and giving us feedback about problems that they might encounter or missing features, inefficiencies and maybe even "infelicities" (a.k.a. bugs). Fixing problems before the release of the 1.0-0 version of "The Matrix", rather than after its release, is our preferred approach