{"id":16,"date":"2024-09-10T07:22:43","date_gmt":"2024-09-09T23:22:43","guid":{"rendered":"http:\/\/chaixiangyu.cn\/?p=16"},"modified":"2024-09-11T21:41:09","modified_gmt":"2024-09-11T13:41:09","slug":"armadillo%e4%bd%bf%e7%94%a8%e4%bb%8b%e7%bb%8d%ef%bc%88%e4%ba%8c%ef%bc%89%ef%bc%9aarmadillo%e8%af%ad%e6%b3%95%e4%b8%8ematlab-octave%e8%af%ad%e6%b3%95%e7%9a%84%e8%81%94%e7%b3%bb","status":"publish","type":"post","link":"https:\/\/chaixiangyu.cn\/?p=16","title":{"rendered":"Armadillo\u4f7f\u7528\u4ecb\u7ecd\uff08\u4e8c\uff09\uff1aArmadillo\u8bed\u6cd5\u4e0eMatlab\/Octave\u8bed\u6cd5\u7684\u8054\u7cfb"},"content":{"rendered":"\n
Matlab\/Octave<\/th>Armadillo<\/th>\u5907\u6ce8<\/th><\/tr><\/thead>
A(1, 1)<\/td>A(0, 0)<\/td>indexing in Armadillo starts at 0<\/td><\/tr>
A(k, k)<\/td>A(k-1, k-1)<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
size(A,1)<\/td>A.n_rows<\/td>read only<\/td><\/tr>
size(A,2)<\/td>A.n_cols<\/td><\/td><\/tr>
size(Q,3)<\/td>Q.n_slices<\/td>Q is a cube (3D array)<\/td><\/tr>
numel(A)<\/td>A.n_elem<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A(:, k)<\/td>A.col(k)<\/td>this is a conceptual example only; exact conversion from Matlab\/Octave to Armadillo syntax will require taking into account that indexing starts at 0<\/td><\/tr>
A(k, : )<\/td>A.row(k)<\/td><\/td><\/tr>
A(:, p:q)<\/td>A.cols(p, q)<\/td><\/td><\/tr>
A(p:q, : )<\/td>A.rows(p, q)<\/td><\/td><\/tr>
A(p:q, r:s)<\/td>A( span(p,q), span(r,s) )<\/td>A( span(first_row, last_row), span(first_col, last_col) )<\/td><\/tr>
Q(:, :, k)<\/td>Q.slice(k)<\/td>Q is a cube (3D array)<\/td><\/tr>
Q(:, :, t:u)<\/td>Q.slices(t, u)<\/td><\/td><\/tr>
Q(p:q, r:s, t:u)<\/td>Q( span(p,q), span(r,s), span(t,u) )<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A’<\/td>A.t() or trans(A)<\/td>matrix transpose \/ Hermitian transpose<\/td><\/tr>
(for complex matrices, the conjugate of each element is taken)<\/td><\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A = zeros(size(A))<\/td>A.zeros()<\/td><\/td><\/tr>
A = ones(size(A))<\/td>A.ones()<\/td><\/td><\/tr>
A = zeros(k)<\/td>A = zeros(k,k)<\/td><\/td><\/tr>
A = ones(k)<\/td>A = ones(k,k)<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
C = complex(A,B)<\/td>cx_mat C = cx_mat(A,B)<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A .* B<\/td>A % B<\/td>element-wise multiplication<\/td><\/tr>
A .\/ B<\/td>A \/ B<\/td>element-wise division<\/td><\/tr>
A \\ B<\/td>solve(A,B)<\/td>conceptually similar to inv(A)*B, but more efficient<\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A = A + 1;<\/td>A++<\/td><\/td><\/tr>
A = A – 1;<\/td>A–<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A = [ 1 2; 3 4; ]<\/td>A << 1 << 2 << endr<\/td><\/td><\/tr>
<< 3 << 4 << endr;<\/td>element initialisation, with special element endr indicating end of row<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
X = A(: )<\/td>X = vectorise(A)<\/td><\/td><\/tr>
X = [ A B ]<\/td>X = join_horiz(A,B)<\/td><\/td><\/tr>
X = [ A; B ]<\/td>X = join_vert(A,B)<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A<\/td>cout << A << endl; or A.print(“A =”);<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
save \u2011ascii ‘A.dat’ A<\/td>A.save(“A.dat”, raw_ascii);<\/td>Matlab\/Octave matrices saved as ascii are readable by Armadillo (and vice-versa)<\/td><\/tr>
load \u2011ascii ‘A.dat’<\/td>A.load(“A.dat”, raw_ascii);<\/td><\/td><\/tr>
<\/td><\/td><\/td><\/tr>
A = randn(2,3);<\/td>mat A = randn(2,3);<\/td><\/td><\/tr>
B = randn(4,5);<\/td>mat B = randn(4,5);<\/td><\/td><\/tr>
F = { A; B }<\/td>field F(2,1); F(0,0) = A; F(1,0) = B;<\/td>fields store arbitrary objects, such as matrices<\/td><\/tr>
\u53c2\u8003\uff1aArmadillo\u5e93\u6587\u6863syntax conversion table<\/a><\/td><\/td><\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"

Matlab\/Octave Armadillo \u5907\u6ce8 A(1, 1) A(0, 0) indexing in […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-16","post","type-post","status-publish","format-standard","hentry","category-algorithm"],"_links":{"self":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/16","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16"}],"version-history":[{"count":1,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/16\/revisions"}],"predecessor-version":[{"id":17,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/16\/revisions\/17"}],"wp:attachment":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}