| isTriangular {Matrix} | R Documentation |
isTriangular(M) returns a logical indicating
M is a triangular matrix. Analogously,
isDiagonal(M) is true iff M is a diagonal matrix.
Contrary to isSymmetric(), these two functions are
generically from Matrix package, and hence also define methods
for traditional (class "matrix") matrices.
isDiagonal(object) isTriangular(object, ...) ## S4 method for signature 'CsparseMatrix' isTriangular(object, upper = NA)
object |
any R object, typically a matrix (traditional or Matrix package). |
upper |
logical, one of |
... |
potentially further arguments for other methods. |
a (“scalar”) logical, TRUE or FALSE, never NA.
isSymmetric; formal class (and subclasses)
"triangularMatrix" and
"diagonalMatrix".
isTriangular(Diagonal(4)) ## is TRUE: a diagonl matrix is also (both upper and lower) triangular (M <- Matrix(c(1,2,0,1), 2,2)) isTriangular(M) # TRUE (*and* of formal class "dtrMatrix") isTriangular(as(M, "dgeMatrix")) # still triangular, even if not "formally" isTriangular(crossprod(M)) # FALSE isDiagonal(matrix(c(2,0,0,1), 2,2)) # TRUE