# SCM Repository

# View of /pkg/TODO

Parent Directory | Revision Log

Revision

File size: 3778 byte(s)

**1673**- (**download**) (**annotate**)*Mon Nov 6 20:54:26 2006 UTC*(12 years, 11 months ago) by*maechler*File size: 3778 byte(s)

host of changes; mostly indexing(sub-set & -assign) for symmetric and [ cbind(i,j) ]

Check for DimNames propagation in coercion and other operations. ------ - rcond methods for sparseMatrix classes - Report the problem in the Linux ldexp manual page. The second and third calls in the Synopsis should be to ldexpf and ldexpl. - [,] indexing: for sparse "works", but not yet for negative indices! - consider moving alloc3Darray from ./src/Mutils.c to $(RSRC)/src/base/array.c ------ - provide methods for "dspMatrix" and "dppMatrix"! - implement (more) methods for supporting "packed" (symmetric / triangular) matrices; particularly something like pack() and unpack() [to/from our classes from/to "numeric"] --- have already man/unpack.Rd but no method yet! (have some dtr* <-> dtp*) ----- - combine the C functions for multiplication by special forms and solution wrt special forms by using a 'right' argument and a 'classed' argument. [done with dgeMatrix_matrix_mm(); not yet for other classes; and for _crossprod()] - add more comprehensive examples / tests for Schur decomposition - arithmetic for sparse matrices: <sparseMatrix> o <same-dim-sparseMatrix> should return a sparse matrix for at least "+" and "*" , also %%, and "/" and "%/%" at least when the RHS is non-zero a scalar. Challenge: nice implementation (``common non-0''; but Tsparse* is not uniq). ----- - "Math2" , "Math", "Arith": keep triangular and symmetric Matrices when appropriate: particularly desirable for "Math2": round(), signif() - "d" <-> "l" coercion for all "[TCR]" sparse matrices is really trivial: "d" -> "l" : drops the 'x' slot "l" -> "d" : construct an 'x' slot of all '1' We currently have many of these conversions explicitly, e.g. setAs("dsTMatrix", "lsTMatrix", function(from) new("lsTMatrix", i = from@i, j = from@j, uplo = from@uplo, Dim = from@Dim, Dimnames = from@Dimnames)) but I would rather want to automatically construct all these coercion methods at once by a ``method constructor'', i.e., for all "dsparse*" -> "lsparse*" and vice versa. How can one do this {in a documented way} ? - tcrossprod(x, y) : do provide methods for y != NULL calling Lapack's DGEMM for "dense" [2005-12-xx: done for dgeMatrix at least] - BUGlet: Shouldn't lose factorization here: h6 <- Hilbert(6); chol(h6) ; str(h6) # has factor str(H6 <- as(h6, "dspMatrix")) # has lost factor ## and the same in a similar situation involving "dpo", "dpp" - Things like M[upper.tri(M)] are not really most useful for sparse matrices. --> provide generic functions upperTriMatrix(), lowerTriMatrix() both with argument 'diag = TRUE' (which can be set to FALSE of course) which are used to extract a triangle from an arbitrary sparse matrix and return a "dtCMatrix". - Factorizations: LU done; also Schur() for *sparse* Matrices. - band(), triu(), tril() for *all* including "matrix", not just sparse matrices - is.na() method for all our matrices [ ==> which(*, arr.ind=TRUE) might work ] - When we have a packed matrix, it's a waste to go through "full" to "sparse": ==> implement setAs("dspMatrix", "sparseMatrix") setAs("dppMatrix", "sparseMatrix") setAs("dtpMatrix", "sparseMatrix") and the same for "lsp" , "ltp" and "nsp" , "ntp" ! - use .Call(Csparse_drop, M, tol) in more places, both with 'tol = 0.' to drop "values that happen to be 0" and for zapsmall() methods for Csparse* - implement .Call(Csparse_scale, ....) interfacing to cholmod_scale() in src/CHOLMOD/Include/cholmod_matrixops.h : for another function specifically for multiplying a cholmod_sparse object by a diagonal matrix. Use it in %*% and [t]crossprod methods. - chol() and determinant() should ``work'': proper result or "good" error message.

root@r-forge.r-project.org | ViewVC Help |

Powered by ViewVC 1.0.0 |