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| 1 | +# this is stats::filter 'as.is' |
| 2 | + |
| 3 | +filter <- function(x, filter, method = c("convolution", "recursive"), |
| 4 | + sides = 2L, circular = FALSE, init=NULL) |
| 5 | +{ |
| 6 | + method <- match.arg(method) |
| 7 | + x <- as.ts(x) |
| 8 | + storage.mode(x) <- "double" |
| 9 | + xtsp <- tsp(x) |
| 10 | + n <- as.integer(NROW(x)) |
| 11 | + if (is.na(n)) stop("invalid value of nrow(x)", domain = NA) |
| 12 | + nser <- NCOL(x) |
| 13 | + filter <- as.double(filter) |
| 14 | + nfilt <- as.integer(length(filter)) |
| 15 | + if (is.na(n)) stop("invalid value of length(filter)", domain = NA) |
| 16 | + if(anyNA(filter)) stop("missing values in 'filter'") |
| 17 | + |
| 18 | + if(method == "convolution") { |
| 19 | + if(nfilt > n) stop("'filter' is longer than time series") |
| 20 | + sides <- as.integer(sides) |
| 21 | + if(is.na(sides) || (sides != 1L && sides != 2L)) |
| 22 | + stop("argument 'sides' must be 1 or 2") |
| 23 | + circular <- as.logical(circular) |
| 24 | + if (is.na(circular)) stop("'circular' must be logical and not NA") |
| 25 | + if (is.matrix(x)) { |
| 26 | + y <- matrix(NA, n, nser) |
| 27 | + for (i in seq_len(nser)) |
| 28 | + y[, i] <- .Call(C_cfilter, x[, i], filter, sides, circular) |
| 29 | + } else |
| 30 | + y <- .Call(C_cfilter, x, filter, sides, circular) |
| 31 | + } else { |
| 32 | + if(missing(init)) { |
| 33 | + init <- matrix(0, nfilt, nser) |
| 34 | + } else { |
| 35 | + ni <- NROW(init) |
| 36 | + if(ni != nfilt) |
| 37 | + stop("length of 'init' must equal length of 'filter'") |
| 38 | + if(NCOL(init) != 1L && NCOL(init) != nser) { |
| 39 | + stop(sprintf(ngettext(nser, |
| 40 | + "'init' must have %d column", |
| 41 | + "'init' must have 1 or %d columns", |
| 42 | + domain = "R-stats"), |
| 43 | + nser), domain = NA) |
| 44 | + } |
| 45 | + if(!is.matrix(init)) dim(init) <- c(nfilt, nser) |
| 46 | + } |
| 47 | + ind <- seq_len(nfilt) |
| 48 | + ## NB: this .Call alters its third argument |
| 49 | + if (is.matrix(x)) { |
| 50 | + y <- matrix(NA, n, nser) |
| 51 | + for (i in seq_len(nser)) |
| 52 | + y[, i] <- |
| 53 | + .Call(C_rfilter, x[, i], filter, |
| 54 | + c(rev(init[, i]), double(n)))[-ind] |
| 55 | + } else |
| 56 | + y <- |
| 57 | + .Call(C_rfilter, x, filter, |
| 58 | + c(rev(init[, 1L]), double(n)))[-ind] |
| 59 | + |
| 60 | + } |
| 61 | +# y <- drop(y) |
| 62 | + tsp(y) <- xtsp |
| 63 | + class(y) <- if(nser > 1L) c("mts", "ts") else "ts" |
| 64 | + y |
| 65 | +} |
| 66 | + |
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