lower.tri {base} | R Documentation |
lower.tri(x, diag=FALSE) upper.tri(x, diag=FALSE)
x |
a matrix. |
diag |
logical. Should the diagonal be included? |
Returns a logical
matrix of the same dimension as
x
which is TRUE
for the relevant triangular part of x
.
m2 <- ma <- matrix(1:20, 4, 5) m2[lower.tri(m2)] <- NA m2 all(lower.tri(ma) == !upper.tri(ma, diag=TRUE))