#### Toplevel ``virtual'' class "Matrix" ### Virtual coercions -- via smart "helpers" (-> ./Auxiliaries.R) setAs("Matrix", "sparseMatrix", function(from) as(from, "CsparseMatrix")) setAs("Matrix", "CsparseMatrix", function(from) as_Csparse(from)) setAs("Matrix", "denseMatrix", function(from) as_dense(from)) ## Maybe TODO: ## setAs("Matrix", "nMatrix", function(from) ....) ## Most of these work; this is a last resort: setAs(from = "Matrix", to = "matrix", # do *not* call base::as.matrix() here: function(from) .bail.out.2("coerce", class(from), class(to))) setAs(from = "matrix", to = "Matrix", function(from) Matrix(from)) ## ## probably not needed eventually: ## setAs(from = "ddenseMatrix", to = "matrix", ## function(from) { ## if(length(d <- dim(from)) != 2) stop("dim(.) has not length 2") ## array(from@x, dim = d, dimnames = dimnames(from)) ## }) ## should propagate to all subclasses: setMethod("as.matrix", signature(x = "Matrix"), function(x) as(x, "matrix")) ## for 'Matrix' objects, as.array() should be equivalent: setMethod("as.array", signature(x = "Matrix"), function(x) as(x, "matrix")) ## head and tail apply to all Matrix objects for which subscripting is allowed: setMethod("head", signature(x = "Matrix"), utils::head.matrix) setMethod("tail", signature(x = "Matrix"), utils::tail.matrix) setMethod("drop", signature(x = "Matrix"), function(x) if(all(dim(x) != 1)) x else drop(as(x, "matrix"))) ## slow "fall back" method {subclasses should have faster ones}: setMethod("as.vector", signature(x = "Matrix", mode = "missing"), function(x) as.vector(as(x, "matrix"))) ## mainly need these for "dMatrix" or "lMatrix" respectively, but why not general: setMethod("as.numeric", signature(x = "Matrix"), function(x, ...) as.numeric(as.vector(x))) setMethod("as.logical", signature(x = "Matrix"), function(x, ...) as.logical(as.vector(x))) setMethod("cov2cor", signature(V = "Matrix"), function(V) { ## was as(cov2cor(as(V, "matrix")), "dpoMatrix")) r <- V p <- (d <- dim(V))[1] if(p != d[2]) stop("'V' is not a square matrix") Is <- sqrt(1/diag(V)) # diag( 1/sigma_i ) if(any(!is.finite(Is))) warning("diag(.) had 0 or NA entries; non-finite result is doubtful") Is <- Diagonal(x = Is) r <- Is %*% V %*% Is r[cbind(1L:p,1L:p)] <- 1 # exact in diagonal as(forceSymmetric(r), "dpoMatrix") }) ## "base" has an isSymmetric() S3-generic since R 2.3.0 setMethod("isSymmetric", signature(object = "symmetricMatrix"), function(object, ...) TRUE) setMethod("isSymmetric", signature(object = "triangularMatrix"), ## TRUE iff diagonal: function(object, ...) isDiagonal(object)) setMethod("isTriangular", signature(object = "matrix"), isTriMat) setMethod("isDiagonal", signature(object = "matrix"), .is.diagonal) ## The "catch all" methods -- far from optimal: setMethod("symmpart", signature(x = "Matrix"), function(x) as((x + t(x))/2, "symmetricMatrix")) setMethod("skewpart", signature(x = "Matrix"), function(x) (x - t(x))/2) ## FIXME: do this (similarly as for "ddense.." in C setMethod("symmpart", signature(x = "matrix"), function(x) (x + t(x))/2) setMethod("skewpart", signature(x = "matrix"), function(x) (x - t(x))/2) setMethod("dim", signature(x = "Matrix"), function(x) x@Dim, valueClass = "integer") setMethod("length", "Matrix", function(x) prod(dim(x))) setMethod("dimnames", signature(x = "Matrix"), function(x) x@Dimnames) ## not exported but used more than once for "dimnames<-" method : ## -- or do only once for all "Matrix" classes ?? dimnamesGets <- function (x, value) { d <- dim(x) if (!is.list(value) || length(value) != 2 || !(is.null(v1 <- value[[1]]) || length(v1) == d[1]) || !(is.null(v2 <- value[[2]]) || length(v2) == d[2])) stop(sprintf("invalid dimnames given for '%s' object", class(x))) x@Dimnames <- list(if(!is.null(v1)) as.character(v1), if(!is.null(v2)) as.character(v2)) x } setMethod("dimnames<-", signature(x = "Matrix", value = "list"), dimnamesGets) setMethod("unname", signature("Matrix", force="missing"), function(obj) { obj@Dimnames <- list(NULL,NULL); obj}) setMethod("all", signature(x = "Matrix"), function(x, ..., na.rm) callGeneric(as(x, "lMatrix"), ..., na.rm=na.rm)) setMethod("any", signature(x = "Matrix"), function(x, ..., na.rm) callGeneric(as(x, "lMatrix"), ..., na.rm=na.rm)) ## NOTE: "&" and "|" are now in group "Logic" c "Ops" --> ./Ops.R ## "!" is in ./not.R Matrix <- function (data = NA, nrow = 1, ncol = 1, byrow = FALSE, dimnames = NULL, sparse = NULL, forceCheck = FALSE) { sparseDefault <- function(m) prod(dim(m)) > 2*sum(isN0(as(m, "matrix"))) i.M <- is(data, "Matrix") if(!i.M && inherits(data, "table")) # special treatment class(data) <- "matrix" # "matrix" first for S4 dispatch if(is.null(sparse1 <- sparse) && (i.M || is(data, "matrix"))) sparse <- sparseDefault(data) sM <- FALSE doDN <- TRUE if (i.M) { if(!missing(nrow) || !missing(ncol)|| !missing(byrow)) warning("'nrow', 'ncol', etc, are disregarded when 'data' is \"Matrix\" already") sM <- is(data,"sparseMatrix") if(!forceCheck && ((sparse && sM) || (!sparse && !sM))) return(data) ## else : convert dense <-> sparse -> at end } else if (!is.matrix(data)) { ## cut & paste from "base::matrix" : if (missing(nrow)) nrow <- ceiling(length(data)/ncol) else if (missing(ncol)) ncol <- ceiling(length(data)/nrow) if(length(data) == 1 && is0(data) && !identical(sparse, FALSE)) { ## Matrix(0, ...) : always sparse unless "sparse = FALSE": if(is.null(sparse)) sparse1 <- sparse <- TRUE i.M <- sM <- TRUE isSym <- nrow == ncol ## will be sparse: do NOT construct full matrix! data <- new(paste(if(is.numeric(data)) "d" else if(is.logical(data)) "l" else stop("invalid 'data'"), if(isSym) "s" else "g", "CMatrix", sep=''), p = rep.int(0L, ncol+1L), Dim = as.integer(c(nrow,ncol)), Dimnames = if(is.null(dimnames)) list(NULL,NULL) else dimnames) } else { ## normal case - using .Internal() to avoid more copying if(getRversion() >= "2.7.0") data <- .Internal(matrix(data, nrow, ncol, byrow, dimnames)) else { data <- .Internal(matrix(data, nrow, ncol, byrow)) dimnames(data) <- dimnames } if(is.null(sparse)) sparse <- sparseDefault(data) } doDN <- FALSE } else if(!missing(nrow) || !missing(ncol)|| !missing(byrow)) warning("'nrow', 'ncol', etc, are disregarded for matrix 'data'") ## 'data' is now a "matrix" or "Matrix" if (doDN && !is.null(dimnames)) dimnames(data) <- dimnames ## check for symmetric / triangular / diagonal : isSym <- isSymmetric(data) if((isTri <- !isSym)) isTri <- isTriangular(data) isDiag <- isSym # cannot be diagonal if it isn't symmetric if(isDiag) isDiag <- !isTRUE(sparse1) && isDiagonal(data) ## try to coerce ``via'' virtual classes if(isDiag) { ## diagonal is preferred to sparse ! data <- as(data, "diagonalMatrix") isSym <- FALSE } else if(sparse && !sM) data <- as(data, "sparseMatrix") else if(!sparse) { if(i.M) { ## data is 'Matrix' if(!is(data, "denseMatrix")) data <- as(data, "denseMatrix") } else { ## data is "matrix" (and result "dense" -> go via "general" ctype <- typeof(data) if (ctype == "complex") stop("complex matrices not yet implemented in Matrix package") if (ctype == "integer") ## integer Matrices not yet implemented storage.mode(data) <- "double" data <- new(paste(.M.kind(data), "geMatrix", sep=''), Dim = dim(data), Dimnames = .M.DN(data), x = c(data)) } } if(isTri && !is(data, "triangularMatrix")) { data <- if(attr(isTri,"kind") == "L") tril(data) else triu(data) #was as(data, "triangularMatrix") } else if(isSym && !is(data, "symmetricMatrix")) data <- forceSymmetric(data) #was as(data, "symmetricMatrix") data } ## Methods for operations where one argument is numeric ## Using as.matrix() and rbind() ## in order to get dimnames from names {at least potentially}: setMethod("%*%", signature(x = "Matrix", y = "numeric"), function(x, y) callGeneric(x, as.matrix(y))) setMethod("%*%", signature(x = "numeric", y = "Matrix"), function(x, y) callGeneric(matrix(x, nrow = 1, byrow=TRUE), y)) setMethod("%*%", signature(x = "Matrix", y = "matrix"), function(x, y) callGeneric(x, Matrix(y))) setMethod("%*%", signature(x = "matrix", y = "Matrix"), function(x, y) callGeneric(Matrix(x), y)) setMethod("crossprod", signature(x = "Matrix", y = "numeric"), function(x, y = NULL) callGeneric(x, as.matrix(y))) setMethod("crossprod", signature(x = "numeric", y = "Matrix"), function(x, y = NULL) callGeneric(as.matrix(x), y)) setMethod("crossprod", signature(x = "Matrix", y = "matrix"), function(x, y = NULL) callGeneric(x, Matrix(y))) setMethod("crossprod", signature(x = "matrix", y = "Matrix"), function(x, y = NULL) callGeneric(Matrix(x), y)) ## The as.matrix() promotion seems illogical to MM, ## but is according to help(tcrossprod, package = "base") : setMethod("tcrossprod", signature(x = "Matrix", y = "numeric"), function(x, y = NULL) callGeneric(x, as.matrix(y))) setMethod("tcrossprod", signature(x = "numeric", y = "Matrix"), function(x, y = NULL) callGeneric(as.matrix(x), y)) setMethod("tcrossprod", signature(x = "Matrix", y = "matrix"), function(x, y = NULL) callGeneric(x, Matrix(y))) setMethod("tcrossprod", signature(x = "matrix", y = "Matrix"), function(x, y = NULL) callGeneric(Matrix(x), y)) ## maybe not 100% optimal, but elegant: setMethod("solve", signature(a = "Matrix", b = "missing"), function(a, b, ...) solve(a, Diagonal(nrow(a)))) setMethod("solve", signature(a = "Matrix", b = "numeric"), function(a, b, ...) callGeneric(a, Matrix(b))) setMethod("solve", signature(a = "Matrix", b = "matrix"), function(a, b, ...) callGeneric(a, Matrix(b))) setMethod("solve", signature(a = "matrix", b = "Matrix"), function(a, b, ...) callGeneric(Matrix(a), b)) ## when no sub-class method is found, bail out setMethod("solve", signature(a = "Matrix", b = "Matrix"), function(a, b, ...) .bail.out.2("solve", class(a), class(b))) ## bail-out methods in order to get better error messages setMethod("%*%", signature(x = "Matrix", y = "Matrix"), function (x, y) stop(gettextf('not-yet-implemented method for <%s> %%*%% <%s>', class(x), class(y)))) setMethod("crossprod", signature(x = "Matrix", y = "ANY"), function (x, y = NULL) .bail.out.2(.Generic, class(x), class(y))) setMethod("crossprod", signature(x = "ANY", y = "Matrix"), function (x, y = NULL) .bail.out.2(.Generic, class(x), class(y))) setMethod("tcrossprod", signature(x = "Matrix", y = "ANY"), function (x, y = NULL) .bail.out.2(.Generic, class(x), class(y))) setMethod("tcrossprod", signature(x = "ANY", y = "Matrix"), function (x, y = NULL) .bail.out.2(.Generic, class(x), class(y))) ## cheap fallbacks setMethod("crossprod", signature(x = "Matrix", y = "Matrix"), function(x, y = NULL) t(x) %*% y) setMethod("tcrossprod", signature(x = "Matrix", y = "Matrix"), function(x, y = NULL) x %*% t(y)) ## There are special sparse methods; this is a "fall back": setMethod("kronecker", signature(X = "Matrix", Y = "ANY", FUN = "ANY", make.dimnames = "ANY"), function(X, Y, FUN, make.dimnames, ...) { if(is(X, "sparseMatrix")) warning("using slow kronecker() method") X <- as(X, "matrix") ; Matrix(callGeneric()) }) setMethod("kronecker", signature(X = "ANY", Y = "Matrix", FUN = "ANY", make.dimnames = "ANY"), function(X, Y, FUN, make.dimnames, ...) { if(is(Y, "sparseMatrix")) warning("using slow kronecker() method") Y <- as(Y, "matrix") ; Matrix(callGeneric()) }) ## FIXME: All of these should never be called setMethod("chol", signature(x = "Matrix"), function(x, pivot = FALSE, ...) .bail.out.1(.Generic, class(x))) setMethod("determinant", signature(x = "Matrix"), function(x, logarithm = TRUE, ...) .bail.out.1(.Generic, class(x))) setMethod("diag", signature(x = "Matrix"), function(x, nrow, ncol) .bail.out.1(.Generic, class(x))) setMethod("t", signature(x = "Matrix"), function(x) .bail.out.1(.Generic, class(x))) setMethod("norm", signature(x = "Matrix", type = "character"), function(x, type, ...) .bail.out.1(.Generic, class(x))) setMethod("rcond", signature(x = "Matrix", norm = "character"), function(x, norm, ...) .bail.out.1(.Generic, class(x))) ## for all : setMethod("norm", signature(x = "ANY", type = "missing"), function(x, type, ...) norm(x, type = "O", ...)) setMethod("rcond", signature(x = "ANY", norm = "missing"), function(x, norm, ...) rcond(x, norm = "O", ...)) ## MM: More or less "Cut & paste" from ## --- diff.default() from R/src/library/base/R/diff.R : setMethod("diff", signature(x = "Matrix"), function(x, lag = 1, differences = 1, ...) { if (length(lag) > 1 || length(differences) > 1 || lag < 1 || differences < 1) stop("'lag' and 'differences' must be integers >= 1") xlen <- nrow(x) if (lag * differences >= xlen) return(x[,FALSE][0]) # empty of proper mode i1 <- -1:-lag for (i in 1:differences) x <- x[i1, , drop = FALSE] - x[-nrow(x):-(nrow(x)-lag+1), , drop = FALSE] x }) setMethod("image", "Matrix", function(x, ...) { # coercing to sparse is not inefficient, ## since we need 'i' and 'j' for levelplot() x <- as(as(x, "sparseMatrix"), "dMatrix") callGeneric() }) ## Group Methods ##-> see ./Ops.R ## ~~~~~ ## For all non-dMatrix objects, and note that "all" and "any" have their own setMethod("Summary", signature(x = "Matrix", na.rm = "ANY"), function(x, ..., na.rm) callGeneric(as(x,"dMatrix"), ..., na.rm = na.rm)) ### -------------------------------------------------------------------------- ### ### Subsetting "[" and ### SubAssign "[<-" : The "missing" cases can be dealt with here, "at the top": ## Using "index" for indices should allow ## integer (numeric), logical, or character (names!) indices : ## "x[]": setMethod("[", signature(x = "Matrix", i = "missing", j = "missing", drop = "ANY"), function (x, i, j, ..., drop) x) ## missing 'drop' --> 'drop = TRUE' ## ----------- ## select rows __ or __ vector indexing: setMethod("[", signature(x = "Matrix", i = "index", j = "missing", drop = "missing"), function(x,i,j, ..., drop) { if(nargs() == 2) { ## e.g. M[0] , M[TRUE], M[1:2] if(any(as.logical(i)) || prod(dim(x)) == 0) ## FIXME: for *large sparse*, use sparseVector ! as.vector(x)[i] else ## save memory (for large sparse M): as.vector(x[1,1])[FALSE] } else { callGeneric(x, i=i, , drop=TRUE) ## ^^ } }) ## select columns setMethod("[", signature(x = "Matrix", i = "missing", j = "index", drop = "missing"), function(x,i,j, ..., drop) callGeneric(x, j=j, drop= TRUE)) setMethod("[", signature(x = "Matrix", i = "index", j = "index", drop = "missing"), function(x,i,j, ..., drop) callGeneric(x, i=i, j=j, drop= TRUE)) ## bail out if any of (i,j,drop) is "non-sense" setMethod("[", signature(x = "Matrix", i = "ANY", j = "ANY", drop = "ANY"), function(x,i,j, ..., drop) stop("invalid or not-yet-implemented 'Matrix' subsetting")) ## logical indexing, such as M[ M >= 7 ] *BUT* also M[ M[,1] >= 3,], ## The following is *both* for M [ ] ## and also for M [ , ] .M.sub.i.logical <- function (x, i, j, ..., drop) { nA <- nargs() if(nA == 2) { ## M [ M >= 7 ] ## FIXME: when both 'x' and 'i' are sparse, this can be very inefficient if(is(x, "sparseMatrix")) message("[ ] : .M.sub.i.logical() maybe inefficient") toC <- geClass(x) if(canCoerce(x, toC)) as(x, toC)@x[as.vector(i)] else as(as(as(x, "generalMatrix"), "denseMatrix"), toC)@x[as.vector(i)] ## -> error when lengths don't match } else if(nA == 3) { ## M [ M[,1, drop=FALSE] >= 7, ] stop("not-yet-implemented 'Matrix' subsetting") ## FIXME } else stop("nargs() = ", nA, ". Extraneous illegal arguments inside '[ .. ]' (i.logical)?") } setMethod("[", signature(x = "Matrix", i = "lMatrix", j = "missing", drop = "ANY"), .M.sub.i.logical) setMethod("[", signature(x = "Matrix", i = "logical", j = "missing", drop = "ANY"), .M.sub.i.logical) subset.ij <- function(x, ij) { m <- nrow(ij) if(m > 3) { cld <- getClassDef(class(x)) sym.x <- extends(cld, "symmetricMatrix") if(sym.x) { W <- if(x@uplo == "U") # stored only [i,j] with i <= j ij[,1] > ij[,2] else ij[,1] < ij[,2] if(any(W)) ij[W,] <- ij[W, 2:1] } if(extends(cld, "sparseMatrix")) { ## do something smarter: nr <- nrow(x) if(!extends(cld, "CsparseMatrix")) { x <- as(x, "CsparseMatrix") # simpler; our standard cld <- getClassDef(class(x)) } tri.x <- extends(cld, "triangularMatrix") if(tri.x) { ## need these for the 'x' slot in any case if (x@diag == "U") x <- .Call(Csparse_diagU2N, x) ## slightly more efficient than non0.i() or non0ind(): ij.x <- .Call(compressed_non_0_ij, x, isC=TRUE) } else { ## symmetric / general : for symmetric, only "existing"b ij.x <- non0.i(x, cld) } mi <- match(encodeInd(ij.x, nr), encodeInd(ij -1L, nr), nomatch=0) mmi <- mi != 0 ## Result: ans <- vector(mode = .type.kind[.M.kindC(cld)], length = m) ## those that are *not* zero: ans[mi[mmi]] <- if(extends(cld, "nsparseMatrix")) TRUE else x@x[mmi] ans } else { ## non-sparse : dense ##---- NEVER happens: 'denseMatrix' has its own setMethod(.) ! message("m[ ]: inefficiently indexing single elements") i1 <- ij[,1] i2 <- ij[,2] ## very inefficient for large m unlist(lapply(seq_len(m), function(j) x[i1[j], i2[j]])) } } else { # 1 <= m <= 3 i1 <- ij[,1] i2 <- ij[,2] unlist(lapply(seq_len(m), function(j) x[i1[j], i2[j]])) } } ## A[ ij ] where ij is (i,j) 2-column matrix -- but also when that is logical mat! .M.sub.i.2col <- function (x, i, j, ..., drop) { nA <- nargs() if(nA == 2) { ## M [ cbind(ii,jj) ] or M [ ] if(!is.integer(nc <- ncol(i))) stop(".M.sub.i.2col(): 'i' has no integer column number;\n", "should never happen; please report") if(is.logical(i)) return(.M.sub.i.logical(x, i=i)) # call with 2 args! else if(!is.numeric(i) || nc != 2) stop("such indexing must be by logical or 2-column numeric matrix") m <- nrow(i) if(m == 0) return(vector(mode = .type.kind[.M.kind(x)])) ## else subset.ij(x, i) } else stop("nargs() = ", nA, ". Extraneous illegal arguments inside '[ .. ]' (i.2col)?") } setMethod("[", signature(x = "Matrix", i = "matrix", j = "missing"),# drop="ANY" .M.sub.i.2col) ### "[<-" : ----------------- ## x[] <- value : setReplaceMethod("[", signature(x = "Matrix", i = "missing", j = "missing", value = "ANY"),## double/logical/... function (x, value) { ## Fails for 'nMatrix' ... FIXME : make sure have method there x@x <- rep(value, length = length(x@x)) validObject(x)# check if type and lengths above match x }) ## A[ ij ] <- value, where ij is (i,j) 2-column matrix : ## ---------------- ## The cheap general method --- FIXME: provide special ones; done for Tsparse.. ## NOTE: need '...' below such that setMethod() does ## not use .local() such that nargs() will work correctly: .M.repl.i.2col <- function (x, i, j, ..., value) { nA <- nargs() if(nA == 3) { ## M [ cbind(ii,jj) ] <- value or M [ Lmat ] <- value if(!is.integer(nc <- ncol(i))) stop(".M.repl.i.2col(): 'i' has no integer column number;\n", "should never happen; please report") else if(!is.numeric(i) || nc != 2) stop("such indexing must be by logical or 2-column numeric matrix") if(is.logical(i)) { message(".M.repl.i.2col(): drop 'matrix' case ...") ## c(i) : drop "matrix" to logical vector return( callGeneric(x, i=c(i), value=value) ) } if(!is.integer(i)) storage.mode(i) <- "integer" if(any(i < 0)) stop("negative values are not allowed in a matrix subscript") if(any(is.na(i))) stop("NAs are not allowed in subscripted assignments") if(any(i0 <- (i == 0))) # remove them i <- i[ - which(i0, arr.ind = TRUE)[,"row"], ] ## now have integer i >= 1 m <- nrow(i) ## mod.x <- .type.kind[.M.kind(x)] if(length(value) > 0 && m %% length(value) != 0) warning("number of items to replace is not a multiple of replacement length") ## recycle: value <- rep(value, length = m) i1 <- i[,1] i2 <- i[,2] if(m > 2) message("m[ ] <- v: inefficiently treating single elements") ## inefficient -- FIXME -- (also loses "symmetry" unnecessarily) for(k in seq_len(m)) x[i1[k], i2[k]] <- value[k] x } else stop("nargs() = ", nA, ". Extraneous illegal arguments inside '[ .. ]' ?") } setReplaceMethod("[", signature(x = "Matrix", i = "matrix", j = "missing", value = "replValue"), .M.repl.i.2col) setReplaceMethod("[", signature(x = "Matrix", i = "missing", j = "ANY", value = "Matrix"), function (x, i, j, ..., value) callGeneric(x=x, , j=j, value = as.vector(value))) setReplaceMethod("[", signature(x = "Matrix", i = "ANY", j = "missing", value = "Matrix"), function (x, i, j, ..., value) callGeneric(x=x, i=i, , value = as.vector(value))) setReplaceMethod("[", signature(x = "Matrix", i = "ANY", j = "ANY", value = "Matrix"), function (x, i, j, ..., value) callGeneric(x=x, i=i, j=j, value = as.vector(value))) setReplaceMethod("[", signature(x = "Matrix", i = "missing", j = "ANY", value = "matrix"), function (x, i, j, ..., value) callGeneric(x=x, , j=j, value = c(value))) setReplaceMethod("[", signature(x = "Matrix", i = "ANY", j = "missing", value = "matrix"), function (x, i, j, ..., value) callGeneric(x=x, i=i, , value = c(value))) setReplaceMethod("[", signature(x = "Matrix", i = "ANY", j = "ANY", value = "matrix"), function (x, i, j, value) callGeneric(x=x, i=i, j=j, value = c(value))) ## (ANY,ANY,ANY) is used when no `real method' is implemented : setReplaceMethod("[", signature(x = "Matrix", i = "ANY", j = "ANY", value = "ANY"), function (x, i, j, value) { if(!is.atomic(value)) stop(sprintf("RHS 'value' (class %s) matches 'ANY', but must match matrix class %s", class(value),class(x))) else stop("not-yet-implemented 'Matrix[<-' method") })