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[matrix] Annotation of /pkg/inst/doc/Announce.txt
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Annotation of /pkg/inst/doc/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 : maechler 2151 As some of you have noticed, the version numbers (current is version
5 : maechler 2157 0.999375-8) are converging to one, and we feel that we have solved
6 : maechler 2151 enough of the many (mostly small) problems to announce that release
7 :     1.0-0 is imminent.
8 : maechler 2131
9 : maechler 2151
10 : maechler 2131 In the DESCRIPTION of the package we say
11 :     --------------------------------------------------------------
12 :     Title: A Matrix package for R
13 :     Author: Douglas Bates <....> and Martin Maechler <....>
14 :     Maintainer: Doug and Martin <Matrix-authors@R-project.org>
15 :     Description: Classes and methods for dense and sparse matrices and
16 :     operations on them using Lapack, CSparse and CHOLMOD
17 :     --------------------------------------------------------------
18 :    
19 :     The Matrix package provides efficient methods for several formal
20 :     (i.e. S4) classes of matrices where each of the actual classes are
21 :     some combination of the following three categories
22 :    
23 :     1) dense or sparse
24 :     2) symmmetric, triangular, diagonal or "general" (or "permutation")
25 :     3) numeric ("d"ouble), logical (TRUE/FALSE/NA) or "patter[n]" (0/1) matrices
26 :    
27 :     Interfaces to many efficient algorithms from Lapack (for "dense") and from
28 :     CHOLMOD / Csparse (for "sparse") are all implemented via method definitions
29 :     for the customary linear algebra functions
30 :     %*%, t(), crossprod(), tcrossprod(), chol(), qr(), solve(),
31 : maechler 2144 colSums(), rowSums(), kronecker(), determinant(), ...
32 : maechler 2131 and for various formal groups of generics, such as
33 :     "Math" (sin,exp,gamma,..) "Arith" (+,-,*,...),
34 : maechler 2144 "Logic" (>, <=, ..), "Summary" (sum, max, ...) etc;
35 :     is.na()
36 : maechler 2131
37 : maechler 2151 Furthermore, 'indexing' : "A[...]" and "A[..] <- value" of
38 :     all(!) kinds of S/R indexing and some new generic functions such as
39 : maechler 2131
40 :     lu() {LU decomposition}
41 : maechler 2157 Schur(), BunchKaufman(),
42 : maechler 2131 norm(), rcond() {Matrix norms and condition numbers}
43 :     expm() {Matrix exponential},
44 :     band(), triu(), tril() {extract band-diagonal or triangular sub-matrices}
45 :     symmpart(), skewpart() { (x + t(x))/2 and (x - t(x)) / 2 }
46 :    
47 : maechler 2151 are provided. Further, an extension to the xtabs function
48 : maechler 2131 xtabs(*, sparse=TRUE)
49 :     for large sparse, two-way contingency tables
50 :     and coercion of one *factor* (possibly crossed with one <numeric>)
51 :     to the corresponding (potentially huge) sparse model matrix for sparse
52 :     least squares and related computations.
53 :    
54 :     Further to the above, "Matrix" objects are also constructed by
55 :     Matrix(), spMatrix(), bdiag() {block-diagonal}, Diagonal() and many
56 :     as(., "....Matrix") possibilities.
57 :    
58 :     The Matrix package also provides a C level API (header files of
59 :     exported C functions providing low-level functionality) to many of its
60 :     internal algorithms that other packages can link to. Currently, the
61 :     'lme4' package makes heavy use of these exported C functions.
62 :    
63 :     ---------------------------------------------------------------------------
64 :    
65 :     One of the things we plan to improve considerably is the documentation
66 :     for the package. Currently there are four vignettes but all but the
67 :    
68 :     Comparisons: Comparisons of Least Squares calculation speeds
69 :    
70 :     are really not complete in one way or another.
71 :    
72 :     ---------------------------------------------------------------------------
73 :    
74 :     We would appreciate current users of the Matrix package (and also
75 :     generally interested useRs) exploring the package's capabilities and
76 :     giving us feedback about problems that they might encounter or missing
77 :     features, inefficiencies and maybe even "infelicities" (a.k.a. bugs).
78 :     Fixing problems before the release of the 1.0-0 version of "The Matrix",
79 :     rather than after its release, is our preferred approach

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