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[matrix] Annotation of /pkg/Announce.txt
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Annotation of /pkg/Announce.txt

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1 : maechler 2131 This weekend, a new version of "the Matrix" (well, actually the R
2 :     package named "Matrix") will become available on the CRAN mirrors.
3 :    
4 :     As some of you have noticed, the version numbers (this is version
5 :     version 0.999375-6) are converging to one, and we feel that we have
6 :     solved enough of the many (mostly small) problems to announce that
7 :     release 1.0-0 is imminent.
8 :    
9 :     In the DESCRIPTION of the package we say
10 :     --------------------------------------------------------------
11 :     Title: A Matrix package for R
12 :     Author: Douglas Bates <....> and Martin Maechler <....>
13 :     Maintainer: Doug and Martin <Matrix-authors@R-project.org>
14 :     Description: Classes and methods for dense and sparse matrices and
15 :     operations on them using Lapack, CSparse and CHOLMOD
16 :     --------------------------------------------------------------
17 :    
18 :     The Matrix package provides efficient methods for several formal
19 :     (i.e. S4) classes of matrices where each of the actual classes are
20 :     some combination of the following three categories
21 :    
22 :     1) dense or sparse
23 :     2) symmmetric, triangular, diagonal or "general" (or "permutation")
24 :     3) numeric ("d"ouble), logical (TRUE/FALSE/NA) or "patter[n]" (0/1) matrices
25 :    
26 :     Interfaces to many efficient algorithms from Lapack (for "dense") and from
27 :     CHOLMOD / Csparse (for "sparse") are all implemented via method definitions
28 :     for the customary linear algebra functions
29 :     %*%, t(), crossprod(), tcrossprod(), chol(), qr(), solve(),
30 :     colSums(), rowSums(), kronecker(), ...
31 :     and for various formal groups of generics, such as
32 :     "Math" (sin,exp,gamma,..) "Arith" (+,-,*,...),
33 :     "Logic" (>, <=, ..), "Summary" (sum, max, ...) etc
34 :    
35 :     Furthermore, 'indexing' : "A[...]" and "A[..] <- value"
36 :     and some new generic functions such as
37 :    
38 :     lu() {LU decomposition}
39 :     Schur()
40 :     norm(), rcond() {Matrix norms and condition numbers}
41 :     expm() {Matrix exponential},
42 :     band(), triu(), tril() {extract band-diagonal or triangular sub-matrices}
43 :     symmpart(), skewpart() { (x + t(x))/2 and (x - t(x)) / 2 }
44 :    
45 :     are provided. Further, an extension to the xtabs function
46 :     xtabs(*, sparse=TRUE)
47 :     for large sparse, two-way contingency tables
48 :     and coercion of one *factor* (possibly crossed with one <numeric>)
49 :     to the corresponding (potentially huge) sparse model matrix for sparse
50 :     least squares and related computations.
51 :    
52 :     Further to the above, "Matrix" objects are also constructed by
53 :     Matrix(), spMatrix(), bdiag() {block-diagonal}, Diagonal() and many
54 :     as(., "....Matrix") possibilities.
55 :    
56 :     The Matrix package also provides a C level API (header files of
57 :     exported C functions providing low-level functionality) to many of its
58 :     internal algorithms that other packages can link to. Currently, the
59 :     'lme4' package makes heavy use of these exported C functions.
60 :    
61 :     ---------------------------------------------------------------------------
62 :    
63 :     One of the things we plan to improve considerably is the documentation
64 :     for the package. Currently there are four vignettes but all but the
65 :    
66 :     Comparisons: Comparisons of Least Squares calculation speeds
67 :    
68 :     are really not complete in one way or another.
69 :    
70 :     ---------------------------------------------------------------------------
71 :    
72 :     We would appreciate current users of the Matrix package (and also
73 :     generally interested useRs) exploring the package's capabilities and
74 :     giving us feedback about problems that they might encounter or missing
75 :     features, inefficiencies and maybe even "infelicities" (a.k.a. bugs).
76 :     Fixing problems before the release of the 1.0-0 version of "The Matrix",
77 :     rather than after its release, is our preferred approach

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