LowerTriangular.test {Matrix}R Documentation

Test a Matrix for Triangularity

Description

LowerTriangular.test (UpperTriangular.test) returns the maximum modulus of the strict upper (lower) triangle of x. is.LowerTriangular and is.UpperTriangular check if this value is less than a tolerance.

Usage

is.LowerTriangular(x, tol = 0)
is.UpperTriangular(x, tol = 0)
LowerTriangular.test(x)
UpperTriangular.test(x)

Arguments

x a numeric or complex matrix.
tol tolerance for the maximum modulus of the elements in the upper (or lower) triangle of the matrix.

Value

LowerTriangular.test (UpperTriangular.test) returns the maximum modulus of the elements in the strict upper (lower) triangle of the matrix x.
is.LowerTriangular (is.UpperTriangular) returns a logical value according to whether the result of LowerTriangular.test (UpperTriangular.test) is less than or equal to tol.

Examples

x <- hilbert(9)
x[row(x) > col(x)] <- 0
is.UpperTriangular(x, tol = 0)
UpperTriangular.test(x)
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