1d:T79f,# Coerce a `covTP` Object into a List Coerce a `covTP` object representing a Tensor-Product covariance kernel on the $d$-dimensional Euclidean space into a list containing $d$ one-dimensional kernels. ```r ## S4 method for signature 'covTP' as.list(x) ``` ## Arguments - `x`: A `covTP` object representing a Tensor-Product covariance kernel. ## Returns A list with length `d` or `d + 1` where `d` is the "dimension" slot `x@d` of the object `x`. The first `d` elements of the list are one-dimensional **correlation** kernel objects with class `"covTP"`. When `x` is a **covariance** kernel (as opposed to a **correlation** kernel), the list contains one more element which gives the variance. ## Caution When `x` is not a correlation kernel the `(d + 1)`-th element of the returned list may be different in future versions: it may be a constant covariance kernel. ## Examples ```r set.seed(123) d <- 6 myCov1 <- covTP(d = d, cov = "corr") coef(myCov1) <- as.vector(simulPar(myCov1, nsim = 1)) as.list(myCov1) ## more examples and check the value of a 'covMat' L <- list() myCov <- list() myCov[[1]] <- covTP(d = d, cov = "corr") coef(myCov[[1]]) <- as.vector(simulPar(myCov[[1]], nsim = 1)) L[[1]] <- as.list(myCov[[1]]) myCov[[2]] <- covTP(k1Fun1 = k1Fun1PowExp, d = d, cov = "corr") coef(myCov[[2]]) <- as.vector(simulPar(myCov[[2]], nsim = 1)) L[[2]] <- as.list(myCov[[2]]) myCov[[3]] <- covTP(k1Fun1 = k1Fun1PowExp, d = d, iso1 = 0L, cov = "corr") coef(myCov[[3]]) <- as.vector(simulPar(myCov[[3]], nsim = 1)) L[[3]] <- as.list(myCov[[3]]) n <- 10 X <- matrix(runif(n * d), nrow = n, dimnames = list(NULL, paste("x", 1:d, sep = ""))) for (iTest in 1:3) { C <- covMat(L[[iTest]][[1]], X[ , 1, drop = FALSE]) for (j in 2:d) { C <- C * covMat(L[[iTest]][[j]], X[ , j, drop = FALSE]) } CTest <- covMat(myCov[[iTest]], X) print(max(abs(abs(C - CTest)))) } ``` ## See Also `covTP` and `covTP-class`.

as.list.covTP function