diagind

diagind(M[, k])

A Range giving the indices of the kth diagonal of the matrix M.

Examples

In the Julia programming language, the function diagind(M[, k]) is used to generate a range of indices corresponding to the kth diagonal of a matrix M.

Get the main diagonal indices:
```
julia> M = [1 2 3; 4 5 6; 7 8 9];
julia> diagind(M)
3-element UnitRange{Int64}:
1:4:9
```
This example returns the indices [1, 5, 9], which represent the main diagonal elements of the matrix M.
Get the first upper diagonal indices:
```
julia> M = [1 2 3; 4 5 6; 7 8 9];
julia> diagind(M, 1)
2-element UnitRange{Int64}:
2:4:8
```
It returns the indices [2, 6], which represent the elements of the first upper diagonal of the matrix M.
Get the second lower diagonal indices:
```
julia> M = [1 2 3; 4 5 6; 7 8 9];
julia> diagind(M, -2)
1-element UnitRange{Int64}:
7:8
```
It returns the indices [7], which represent the elements of the second lower diagonal of the matrix M.

Common mistake example:

julia> M = [1 2 3; 4 5 6; 7 8 9];
julia> diagind(M, 5)
ERROR: ArgumentError: k=5 is out of range. Expected -2:k_max=2.

In this example, the value of k is out of the valid range for the given matrix M. It's important to ensure that the value of k is within the valid range specified by -2 to k_max (maximum diagonal index) for the matrix.

Ac_ldiv_B, Ac_ldiv_Bc, Ac_mul_B, Ac_mul_Bc, Ac_rdiv_B, Ac_rdiv_Bc, At_ldiv_B, At_ldiv_Bt, At_mul_B, At_mul_Bt, At_rdiv_B, At_rdiv_Bt, A_ldiv_Bc, A_ldiv_Bt, A_mul_B!, A_mul_Bc, A_mul_Bt, A_rdiv_Bc, A_rdiv_Bt, Bidiagonal, cond, conv2, det, diag, diagind, diagm, diff, eig, eigvals, eigvecs, expm, eye, full, inv, isdiag, ishermitian, isposdef, isposdef!, issym, istril, istriu, logabsdet, logdet, lyap, norm, qrfact, rank, repmat, rot180, rotl90, rotr90, sortrows, sqrtm, SymTridiagonal, trace, Tridiagonal, tril, tril!, triu, triu!, writedlm,

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diagind

Examples

See Also

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