Returns a matrix of logicals the same size as
x which is
TRUE in
the lower triangle or upper triangle.
USAGE:
lower.tri(x, diag=F)
upper.tri(x, diag=F)
REQUIRED ARGUMENTS:
x
a matrix.
OPTIONAL ARGUMENTS:
diag
logical flag: if
TRUE,
then include the diagonal in the lower (or upper) triangle
(that is, make the diagonal elements of the result
TRUE).
VALUE:
matrix of the same dimension as
x
which for
lower.tri is
FALSE
above the diagonal
and
TRUE below the diagonal.
For
upper.tri the matrix is
FALSE
below the diagonal
and
TRUE above the diagonal.
SEE ALSO:
,
.
EXAMPLES:
lower.tri(freeny.x)
upper.tri(freeny.x, T)
# A correlation matrix with 0.5 on all off-diagonals:
corr <- diag(5)
corr[lower.tri(corr)] <- 0.5
corr[upper.tri(corr)] <- 0.5
corr