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| Syntax |
diag(A)A, k)
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| See Also | identity , triu , tril , seq |
diag returns a square matrix, of minimal dimension,
that is zero except for its k-th diagonal which is equal to A.
If A is a matrix,
diag returns the k-th diagonal of the matrix A.
If the argument k is not present,
the value zero is used in its place.
k >= 0, the k-th diagonal of a matrix B
is the column vector consisting
of the sequence of elements B(1, 1+k), B(2, 2+k), ... ,
where the sequence continues as long as both indices are within the matrix.
If k <= 0, the k-th diagonal of a matrix B
is the column vector consisting
of the sequence of elements B(1-k, 1), B(2-k, 2), ... ,
where the sequence continues as long as both indices are within the matrix.
A = {1, 2}
k = 1
diag(A, k)
O-Matrix will respond
{
[ 0 , 1 , 0 ]
[ 0 , 0 , 2 ]
[ 0 , 0 , 0 ]
}
A = {[1, 2, 3] , [4, 5, 6], [7, 8, 9]}
k = -1
diag(A, k)
O-Matrix will respond
{
4
8
}