trace

trace(M)

Matrix trace

Examples

The trace function in Julia calculates the sum of diagonal elements of a matrix.

julia> A = [1 2 3; 4 5 6; 7 8 9]
3×3 Array{Int64,2}:
 1  2  3
 4  5  6
 7  8  9

julia> trace(A)
15

Here are some common examples of how to use the trace function:

Calculate trace of a square matrix:
```
julia> M = [1 2 3; 4 5 6; 7 8 9];
julia> trace(M)
15
```
This calculates the trace of the matrix M which is the sum of the diagonal elements (1 + 5 + 9).
Calculate trace of a larger matrix:
```
julia> M = [1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16];
julia> trace(M)
34
```
It works with matrices of any size as long as they are square.

Common mistake example:

julia> M = [1 2; 3 4; 5 6];
julia> trace(M)
ERROR: MethodError: no method matching trace(::Array{Int64,2})

In this example, the input matrix M is not a square matrix. The trace function can only be applied to square matrices. Ensure that the input matrix is square to avoid such errors.

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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trace

Examples

See Also

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