| Matlab/Octave | Armadillo | 备注 |
|---|---|---|
| A(1, 1) | A(0, 0) | indexing in Armadillo starts at 0 |
| A(k, k) | A(k-1, k-1) | |
| size(A,1) | A.n_rows | read only |
| size(A,2) | A.n_cols | |
| size(Q,3) | Q.n_slices | Q is a cube (3D array) |
| numel(A) | A.n_elem | |
| A(:, k) | A.col(k) | this is a conceptual example only; exact conversion from Matlab/Octave to Armadillo syntax will require taking into account that indexing starts at 0 |
| A(k, : ) | A.row(k) | |
| A(:, p:q) | A.cols(p, q) | |
| A(p:q, : ) | A.rows(p, q) | |
| A(p:q, r:s) | A( span(p,q), span(r,s) ) | A( span(first_row, last_row), span(first_col, last_col) ) |
| Q(:, :, k) | Q.slice(k) | Q is a cube (3D array) |
| Q(:, :, t:u) | Q.slices(t, u) | |
| Q(p:q, r:s, t:u) | Q( span(p,q), span(r,s), span(t,u) ) | |
| A’ | A.t() or trans(A) | matrix transpose / Hermitian transpose |
| (for complex matrices, the conjugate of each element is taken) | ||
| A = zeros(size(A)) | A.zeros() | |
| A = ones(size(A)) | A.ones() | |
| A = zeros(k) | A = zeros(k,k) | |
| A = ones(k) | A = ones(k,k) | |
| C = complex(A,B) | cx_mat C = cx_mat(A,B) | |
| A .* B | A % B | element-wise multiplication |
| A ./ B | A / B | element-wise division |
| A \ B | solve(A,B) | conceptually similar to inv(A)*B, but more efficient |
| A = A + 1; | A++ | |
| A = A – 1; | A– | |
| A = [ 1 2; 3 4; ] | A << 1 << 2 << endr | |
| << 3 << 4 << endr; | element initialisation, with special element endr indicating end of row | |
| X = A(: ) | X = vectorise(A) | |
| X = [ A B ] | X = join_horiz(A,B) | |
| X = [ A; B ] | X = join_vert(A,B) | |
| A | cout << A << endl; or A.print(“A =”); | |
| save ‑ascii ‘A.dat’ A | A.save(“A.dat”, raw_ascii); | Matlab/Octave matrices saved as ascii are readable by Armadillo (and vice-versa) |
| load ‑ascii ‘A.dat’ | A.load(“A.dat”, raw_ascii); | |
| A = randn(2,3); | mat A = randn(2,3); | |
| B = randn(4,5); | mat B = randn(4,5); | |
| F = { A; B } | field F(2,1); F(0,0) = A; F(1,0) = B; | fields store arbitrary objects, such as matrices |
| 参考：Armadillo库文档syntax conversion table |
Armadillo使用介绍（二）：Armadillo语法与Matlab/Octave语法的联系
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