det.LowerTriangular(x, logarithm=T) det.UpperTriangular(x, logarithm=T) det.UnitLowerTriangular(x, logarithm=T) det.UnitUpperTriangular(x, logarithm=T)
x <- Matrix( sample(-3:3, size = 9, replace = T), nrow = 3, ncol = 3) x[row(x) > col(x)] <- 0 # construct triangular matrix class(x) <- Matrix.class(x) det(x)