[
top
|
up
]
Lower and Upper Triangular Part of a Matrix
Syntax
lower.tri(x, diag=FALSE) upper.tri(x, diag=FALSE)
Arguments
x
a matrix.
diag
logical. Should the diagonal be included?
Value
Returns a
logical
matrix of the same dimension as
x
which is
TRUE
for the relevant triangular part of
x
.
See Also
diag
,
matrix
.
Examples
m2 <- ma <- matrix(1:20, 4, 5) m2[lower.tri(m2)] <- NA m2 all(lower.tri(ma) == !upper.tri(ma, diag=TRUE))