| # File src/library/stats/R/filter.R |
| # Part of the R package, https://www.R-project.org |
| # |
| # Copyright (C) 1999-2017 The R Core Team |
| # |
| # This program is free software; you can redistribute it and/or modify |
| # it under the terms of the GNU General Public License as published by |
| # the Free Software Foundation; either version 2 of the License, or |
| # (at your option) any later version. |
| # |
| # This program is distributed in the hope that it will be useful, |
| # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| # GNU General Public License for more details. |
| # |
| # A copy of the GNU General Public License is available at |
| # https://www.R-project.org/Licenses/ |
| |
| filter <- function(x, filter, method = c("convolution", "recursive"), |
| sides = 2L, circular = FALSE, init=NULL) |
| { |
| method <- match.arg(method) |
| x <- as.ts(x) |
| storage.mode(x) <- "double" |
| xtsp <- tsp(x) |
| n <- as.integer(NROW(x)) |
| if (is.na(n)) stop(gettextf("invalid value of %s", "NROW(x)"), domain = NA) |
| nser <- NCOL(x) |
| filter <- as.double(filter) |
| nfilt <- as.integer(length(filter)) |
| if (is.na(nfilt)) stop(gettextf("invalid value of %s", "length(filter)"), |
| domain = NA) |
| if(anyNA(filter)) stop("missing values in 'filter'") |
| |
| if(method == "convolution") { |
| if(nfilt > n) stop("'filter' is longer than time series") |
| sides <- as.integer(sides) |
| if(is.na(sides) || (sides != 1L && sides != 2L)) |
| stop("argument 'sides' must be 1 or 2") |
| circular <- as.logical(circular) |
| if (is.na(circular)) stop("'circular' must be logical and not NA") |
| if (is.matrix(x)) { |
| y <- matrix(NA, n, nser) |
| for (i in seq_len(nser)) |
| y[, i] <- .Call(C_cfilter, x[, i], filter, sides, circular) |
| } else |
| y <- .Call(C_cfilter, x, filter, sides, circular) |
| } else { |
| if(missing(init)) { |
| init <- matrix(0, nfilt, nser) |
| } else { |
| ni <- NROW(init) |
| if(ni != nfilt) |
| stop("length of 'init' must equal length of 'filter'") |
| if(NCOL(init) != 1L && NCOL(init) != nser) { |
| stop(sprintf(ngettext(nser, |
| "'init' must have %d column", |
| "'init' must have 1 or %d columns", |
| domain = "R-stats"), |
| nser), domain = NA) |
| } |
| if(!is.matrix(init)) dim(init) <- c(nfilt, nser) |
| } |
| ind <- seq_len(nfilt) |
| ## NB: this .Call alters its third argument |
| if (is.matrix(x)) { |
| y <- matrix(NA, n, nser) |
| for (i in seq_len(nser)) |
| y[, i] <- |
| .Call(C_rfilter, x[, i], filter, |
| c(rev(init[, i]), double(n)))[-ind] |
| } else |
| y <- |
| .Call(C_rfilter, x, filter, |
| c(rev(init[, 1L]), double(n)))[-ind] |
| |
| } |
| # y <- drop(y) |
| tsp(y) <- xtsp |
| class(y) <- if(nser > 1L) c("mts", "ts") else "ts" |
| y |
| } |
| |