| # File src/library/base/R/eigen.R |
| # Part of the R package, https://www.R-project.org |
| # |
| # Copyright (C) 1995-2019 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/ |
| |
| |
| isSymmetric <- function(object, ...) UseMethod("isSymmetric") |
| |
| isSymmetric.matrix <- function(object, tol = 100*.Machine$double.eps, tol1 = 8*tol, ...) |
| { |
| if(!is.matrix(object)) return(FALSE) ## we test for symmetric *matrix* |
| ## cheap pretest: is it square? |
| d <- dim(object) |
| if((n <- d[1L]) != d[2L]) return(FALSE) |
| iCplx <- is.complex(object) |
| if(n > 1L && length(tol1)) { |
| ## initial pre-tests, fast for large non-symmetric: |
| Cj <- if(iCplx) Conj else identity |
| for(i in unique(c(1L, 2L, n-1L, n))) |
| if(is.character(all.equal(object[i, ], Cj(object[, i]), tolerance = tol1, ...))) |
| return(FALSE) |
| } |
| test <- |
| if(iCplx) |
| all.equal.numeric(object, Conj(t(object)), tolerance = tol, ...) |
| else # numeric, character, .. |
| all.equal(object, t(object), tolerance = tol, ...) |
| isTRUE(test) |
| } |
| |
| eigen <- function(x, symmetric, only.values = FALSE, EISPACK = FALSE) |
| { |
| x <- unname(as.matrix(x)) |
| n <- nrow(x) |
| if (!n) stop("0 x 0 matrix") |
| if (n != ncol(x)) stop("non-square matrix in 'eigen'") |
| n <- as.integer(n) |
| if(is.na(n)) stop("invalid nrow(x)") |
| |
| complex.x <- is.complex(x) |
| if (!all(is.finite(x))) stop("infinite or missing values in 'x'") |
| |
| if(missing(symmetric)) symmetric <- isSymmetric.matrix(x) |
| |
| if (symmetric) { |
| z <- if(!complex.x) .Internal(La_rs(x, only.values)) |
| else .Internal(La_rs_cmplx(x, only.values)) |
| ord <- rev(seq_along(z$values)) |
| } else { |
| z <- if(!complex.x) .Internal(La_rg(x, only.values)) |
| else .Internal(La_rg_cmplx(x, only.values)) |
| ord <- sort.list(Mod(z$values), decreasing = TRUE) |
| } |
| if(only.values) |
| list(values = z$values[ord], vectors = NULL) |
| else |
| structure(class = "eigen", |
| list(values = z$values[ord], |
| vectors = z$vectors[, ord, drop = FALSE])) |
| } |
| |
| print.eigen <- function (x, ...) { |
| cat("eigen() decomposition\n") |
| print(unclass(x), ...) |
| invisible(x) |
| } |