# SCM Repository

[matrix] Diff of /pkg/TODO
 [matrix] / pkg / TODO

# Diff of /pkg/TODO

revision 1578, Mon Sep 18 21:02:50 2006 UTC revision 1592, Thu Sep 28 15:31:17 2006 UTC
# Line 72  Line 72
72    (which can be set to FALSE of course) which are used to extract a    (which can be set to FALSE of course) which are used to extract a
73    triangle from an arbitrary sparse matrix and  return a  "dtCMatrix".    triangle from an arbitrary sparse matrix and  return a  "dtCMatrix".
74
75  - Factorizations: LU [ -> solve() ] and Schur()  for  *sparse*  Matrices.  - Factorizations: LU done; also Schur()  for  *sparse*  Matrices.
-----------------  LU-sparse is the purpose of all of ./src/UMFPACK/
-->  ./inst/doc/UFsparse/*
Note that UMFPACK is a bit slow compared to TAUCS etc, according to
Gould et al.(2005)
And then, possibly eigen(), svd(), qr(), ... for sparse
{probably base some on the fast  chol() of CHOLMOD}.
./man/lu.Rd notes that lu() is not yet available for sparse

2006-04-15 : now with 'CSparse' { src/cs.c }, have at least solve( <dtC*> )

- nicer pedigree examples and tests
76
77  - band(), triu(), tril() for *all*, not just sparse matrices  - band(), triu(), tril() for *all*, not just sparse matrices
78
79  - is.na() method for all our matrices [ ==> which(*, arr.ind=TRUE) might work ]  - is.na() method for all our matrices [ ==> which(*, arr.ind=TRUE) might work ]
80
81    - When we have a packed matrix, it's a waste to go through "full" to "sparse":
82      ==> implement
83            setAs("dspMatrix", "sparseMatrix")
84            setAs("dppMatrix", "sparseMatrix")
85            setAs("dtpMatrix", "sparseMatrix")
86      and the same for "lsp" , "ltp"  and  "nsp" , "ntp" !

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