Returns the lower triangle of a matrix.
TRIL(a, d)
a |
- |
A matrix. |
d |
- |
Optional. An integer, the diagonal on and below which to include matrix elements. Defaults to 0, the main diagonal. |
An array consisting of the lower triangle of a where the other elements are zero.
W1: {{1, 2, 3},
{4, 5, 6},
{7, 8, 9}}
W2: tril(W1)
W2 == {{1, 0, 0},
{4, 5, 0},
{7, 8, 9}}
W3: tril(W1, 1)
W3 == {{1, 2, 0},
{4, 5, 6},
{7, 8, 9}}
W4: tril(W1, -1)
W4 == {{0, 0, 0},
{4, 0, 0},
{7, 8, 0}}
TRIL(a, -1) is equivalent to LOTRIX(a).
See TRIU to return the upper matrix.