{"id":46,"date":"2024-09-10T07:29:41","date_gmt":"2024-09-09T23:29:41","guid":{"rendered":"http:\/\/chaixiangyu.cn\/?p=46"},"modified":"2024-09-11T21:39:51","modified_gmt":"2024-09-11T13:39:51","slug":"armadillo%ef%bc%9a%e6%88%90%e5%91%98%e5%87%bd%e6%95%b0%e5%92%8c%e5%8f%98%e9%87%8f%ef%bc%88%e4%b8%80%ef%bc%89","status":"publish","type":"post","link":"https:\/\/chaixiangyu.cn\/?p=46","title":{"rendered":"Armadillo\uff1a\u6210\u5458\u51fd\u6570\u548c\u53d8\u91cf\uff08\u4e00\uff09"},"content":{"rendered":"\n

@[toc]<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u5c5e\u6027<\/h1>\n\n\n\n
.n_rows     \u884c\u6570;\u5b58\u5728\u4e8e Mat\u3001Col\u3001Row\u3001Cube\u3001field \u548c SpMat \u4e2d\n.n_cols     \u5217\u6570;\u5b58\u5728\u4e8e Mat\u3001Col\u3001Row\u3001Cube\u3001field \u548c SpMat \u4e2d\n.n_elem     \u5143\u7d20\u603b\u6570;\u5b58\u5728\u4e8e Mat\u3001Col\u3001Row\u3001Cube\u3001field \u548c SpMat \u4e2d\n.n_slices   \u5207\u7247\u6570\u91cf;\u5b58\u5728\u4e8e\u591a\u7ef4\u6570\u636e\u96c6\u548c\u5b57\u6bb5\u4e2d\n.n_nonzero  \u975e\u96f6\u5143\u7d20\u7684\u6570\u91cf;\u5b58\u5728\u4e8e SpMat \u4e2d<\/code><\/pre>\n\n\n\n
\u53d8\u91cf\u7684\u7c7b\u578b\u4e3a uword<\/p>\n\n\n\n
\u53d8\u91cf\u662f\u53ea\u8bfb\u7684; \u8981\u66f4\u6539\u5927\u5c0f\uff0c\u8bf7\u4f7f\u7528 .set_size\uff08\uff09\u3001.copy_size\uff08\uff09\u3001.zeros\uff08\uff09\u3001.ones\uff08\uff09\u3001 \u6216\u8005 .reset\uff08\uff09<\/p>\n\n\n\n
\u5bf9\u4e8e Col \u548c Row \u7c7b\uff0cn_elem \u8fd8\u6307\u793a\u5411\u91cf\u957f\u5ea6<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat X(4,5);\ncout << \"X has \" << X.n_cols << \" columns\" << endl;<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.set_size()\n.copy_size()\n.zeros()\n.ones()\n.reset()\nsize()<\/code><\/pre>\n\n\n\n
\u901a\u8fc7 \uff08\uff09\u3001[] \u548c .at\uff08\uff09 \u8bbf\u95ee\u5143\u7d20\/\u5bf9\u8c61<\/h1>\n\n\n\n
\u63d0\u4f9b\u5bf9\u5b58\u50a8\u5728\u5bb9\u5668\u5bf9\u8c61\u4e2d\u7684\u5355\u4e2a\u5143\u7d20\u6216\u5bf9\u8c61\u7684\u8bbf\u95ee \uff08\u5373Mat, Col, Row, Cube, field)<\/p>\n\n\n\n
(i) \u5bf9\u4e8e vec \u548c rowvec\uff0c\u8bbf\u95ee\u5b58\u50a8\u5728\u7d22\u5f15 i \u4e2d\u7684\u5143\u7d20\u3002 \u5bf9\u4e8e\u57ab\u3001\u7acb\u65b9\u4f53\u548c\u5b57\u6bb5\uff0c\u5728\u5e73\u9762\u5e03\u5c40\u7684\u5047\u8bbe\u4e0b\u8bbf\u95ee\u5b58\u50a8\u5728\u7d22\u5f15 i \u5904\u7684\u5143\u7d20\/\u5bf9\u8c61\uff0c \u5bf9\u6570\u636e\u8fdb\u884c\u5217\u4f18\u5148\u6392\u5e8f\uff08\u5373\u9010\u5217\uff09\u3002 \u5982\u679c\u8bf7\u6c42\u7684\u5143\u7d20\u8d8a\u754c\uff0c\u5219\u4f1a\u5f15\u53d1\u5f02\u5e38\u3002\n\n.at(i)\u6216[i] \u81f3\u4e8e(i)\uff0c\u6ca1\u6709\u8fb9\u754c\u68c0\u67e5;\u4e0d\u63a8\u8350;\u8bf7\u53c2\u9605\u4e0b\u9762\u7684\u6ce8\u610f\u4e8b\u9879\n\n(r,c)   \u5bf9\u4e8e mat \u548c 2D \u5b57\u6bb5\u7c7b\uff0c\u8bbf\u95ee\u5b58\u50a8\u5728\u7b2c r \u884c\u548c c \u5217\u4e2d\u7684\u5143\u7d20\/\u5bf9\u8c61\u3002 \u5982\u679c\u8bf7\u6c42\u7684\u5143\u7d20\u8d8a\u754c\uff0c\u5219\u4f1a\u5f15\u53d1\u5f02\u5e38\u3002\n\n.at(r,c) \u81f3\u4e8e(r,c)\uff0c\u6ca1\u6709\u8fb9\u754c\u68c0\u67e5;\u4e0d\u63a8\u8350;\u8bf7\u53c2\u9605\u4e0b\u9762\u7684\u6ce8\u610f\u4e8b\u9879\n\n(r,c,s) \u5bf9\u4e8e\u591a\u7ef4\u6570\u636e\u96c6\u548c 3D \u5b57\u6bb5\u7c7b\uff0c\u8bbf\u95ee\u5b58\u50a8\u5728\u7b2c r \u884c\u3001c \u5217\u548c\u5207\u7247 s \u4e2d\u7684\u5143\u7d20\/\u5bf9\u8c61\u3002 \u5982\u679c\u8bf7\u6c42\u7684\u5143\u7d20\u8d8a\u754c\uff0c\u5219\u4f1a\u5f15\u53d1\u5f02\u5e38\u3002\n\n.at(r,c,s)  \n\u81f3\u4e8e \uff0c\u4f46\u6ca1\u6709\u8fb9\u754c\u68c0\u67e5;\u4e0d\u63a8\u8350;\u8bf7\u53c2\u9605\u4e0b\u9762\u7684\u6ce8\u610f\u4e8b\u9879(r,c,s)<\/code><\/pre>\n\n\n\n
\u5143\u7d20\u7684\u7d22\u5f15\u901a\u8fc7 uword \u7c7b\u578b\u6307\u5b9a\uff0cuword \u7c7b\u578b\u662f\u65e0\u7b26\u53f7\u6574\u6570\u7c7b\u578b\u7684 typedef\u3002 \u4f7f\u7528\u5faa\u73af\u8bbf\u95ee\u5143\u7d20\u65f6\uff0c\u6700\u597d\u4f7f\u7528 uword \u800c\u4e0d\u662f int\u3002 \u4f8b\u5982\uff1afor(uword i=0; i<X.n_elem; ++i) { X(i) = ... }<\/code><\/p>\n\n\n\n
\u8b66\u544a\uff1a
\u8bbf\u95ee\u65e0\u8fb9\u754c\u5143\u7d20\u68c0\u67e5\u7684\u901f\u5ea6\u7a0d\u5feb\uff0c\u4f46\u5728\u9996\u5148\u5f7b\u5e95\u8c03\u8bd5\u4ee3\u7801\u4e4b\u524d\u4e0d\u5efa\u8bae\u8fd9\u6837\u505a
C++ \u4e2d\u7684\u7d22\u5f15\u4ece 0 \u5f00\u59cb
\u901a\u8fc7[r,c]\u548c[r,c,s]\u8bbf\u95ee\u5143\u7d20\uff0c\u5728 C++ \u4e2d\u4f1a\u65e0\u6cd5\u6b63\u5e38\u5de5\u4f5c; \u8bf7\u6539\u7528 (r,c)\u548c(r,c,s)<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat M(10, 10, fill::randu);\nM(9,9) = 123.0;\ndouble x = M(1,2);\n\nvec v(10, fill::randu);\nv(9) = 123.0;\ndouble y = v(0);<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.in_range()\nelement initialisation\nind2sub()\nsub2ind()\n.index_min() \/ .index_max()\nsubmatrix views\n.memptr()\n.transform()\n.for_each()\niterators (\u5bc6\u96c6\u77e9\u9635)\niterators (\u591a\u7ef4\u6570\u636e\u96c6)\niterators (\u7a00\u758f\u77e9\u9635)\nconfig.hpp<\/code><\/pre>\n\n\n\n
\u5143\u7d20\u521d\u59cb\u5316<\/h1>\n\n\n\n
\u901a\u8fc7\u5e26\u652f\u6491\u7684\u521d\u59cb\u5316\u5668\u5217\u8868\u5728 Mat\u3001Col\u3001Row \u4e2d\u8bbe\u7f6e\u5143\u7d20<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
vec v = { 1, 2, 3 };\n\nmat A = { {1, 3, 5},\n          {2, 4, 6} };<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
element access\n.reshape()\n.print()\nsaving & loading matrices\nadvanced constructors (matrices)<\/code><\/pre>\n\n\n\n
.zeros() \uff08Mat\u3001Col\u3001Row\u3001SpMat\u3001Cube \u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.zeros( n_elem ) \uff08Col \u548c Row \u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.zeros( n_rows\uff0c n_cols ) \uff08Mat \u548c SpMat \u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.zeros( n_rows, n_cols, n_slices )\uff08Cube \u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.zeros(size(X)) \uff08Mat\u3001Col\u3001Row\u3001Cube\u3001SpMat \u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
\u5c06\u5bf9\u8c61\u7684\u5143\u7d20\u8bbe\u7f6e\u4e3a\u96f6\uff0c \uff08\u53ef\u9009\uff09\u9996\u5148\u5c06\u5927\u5c0f\u66f4\u6539\u4e3a\u6307\u5b9a\u5c3a\u5bf8<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A;\nA.zeros(5, 10);   \/\/ or:  mat A(5, 10, fill::zeros);\n\nmat B;\nB.zeros( size(A) );\n\nmat C(5, 10, fill::randu);\nC.zeros();<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
zeros() \uff08\u72ec\u7acb\u51fd\u6570\uff09\n.ones()\n.clean()\n.is_zero()\n.randu()\n.fill()\n.imbue()\n.reset()\n.set_size()\nsize()<\/code><\/pre>\n\n\n\n
.ones() (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.ones( n_elem ) (Col \u548c Row\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.ones( n_rows, n_cols ) (Mat\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.ones( n_rows, n_cols, n_slices ) (Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.ones( size(X) ) (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
\u5c06\u5bf9\u8c61\u7684\u6240\u6709\u5143\u7d20\u8bbe\u7f6e\u4e3a\u4e00\u4e2a\uff0c \uff08\u53ef\u9009\uff09\u9996\u5148\u5c06\u5927\u5c0f\u66f4\u6539\u4e3a\u6307\u5b9a\u5c3a\u5bf8<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A;\nA.ones(5, 10);   \/\/ or:  mat A(5, 10, fill::ones);\n\nmat B;\nB.ones( size(A) );\n\nmat C(5, 10, fill::randu);\nC.ones();<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
ones()  \uff08\u72ec\u7acb\u51fd\u6570\uff09\n.eye()\n.zeros()\n.fill()\n.imbue()\n.randu()\nsize()<\/code><\/pre>\n\n\n\n
.eye()<\/h1>\n\n\n\n
.eye( n_rows, n_cols )<\/h1>\n\n\n\n
.eye( size(X) )<\/h1>\n\n\n\n
Mat \u548c SpMat \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5c06\u6cbf\u4e3b\u5bf9\u89d2\u7ebf\u7684\u5143\u7d20\u8bbe\u7f6e\u4e3a 1\uff0c\u5c06\u975e\u5bf9\u89d2\u7ebf\u5143\u7d20\u8bbe\u7f6e\u4e3a\u96f6\uff0c \uff08\u53ef\u9009\uff09\u9996\u5148\u5c06\u5927\u5c0f\u66f4\u6539\u4e3a\u6307\u5b9a\u5c3a\u5bf8<\/p>\n\n\n\n
\u5f53 n_rows = n_cols \u65f6\uff0c\u5c06\u751f\u6210\u5355\u4f4d\u77e9\u9635<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A;\nA.eye(5, 5);  \/\/ or:  mat A(5, 5, fill::eye);\n\nmat B;\nB.eye( size(A) );\n\nmat C(5, 5, fill::randu);\nC.eye();<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.ones()\n.diag()\ndiagmat()\ndiagvec()\neye()\uff08\u72ec\u7acb\u51fd\u6570\uff09\nsize()<\/code><\/pre>\n\n\n\n
.randu() (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randu( n_elem ) (Col \u548c Row\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randu( n_rows, n_cols ) (Mat\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randu( n_rows, n_cols, n_slices ) (Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randu( size(X) ) (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randn() (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randn( n_elem ) (Col \u548c Row\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randn( n_rows, n_cols ) (Mat\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randn( n_rows, n_cols, n_slices ) (Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.randn( size(X) ) (Mat, Col, Row, Cube\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
\u5c06\u6240\u6709\u5143\u7d20\u8bbe\u7f6e\u4e3a\u968f\u673a\u503c\uff0c \uff08\u53ef\u9009\uff09\u9996\u5148\u5c06\u5927\u5c0f\u66f4\u6539\u4e3a\u6307\u5b9a\u5c3a\u5bf8<\/p>\n\n\n\n
.randu\uff08\uff09 \u5728 [0,1] \u533a\u95f4\u5185\u4f7f\u7528\u5747\u5300\u5206\u5e03<\/p>\n\n\n\n
.randn\uff08\uff09 \u4f7f\u7528\u5747\u503c\u548c\u5355\u4f4d\u65b9\u5dee\u4e3a\u96f6\u7684\u6b63\u6001\/\u9ad8\u65af\u5206\u5e03<\/p>\n\n\n\n
\u5bf9\u4e8e\u590d\u6742\u5143\u7d20\uff0c\u5b9e\u90e8\u548c\u865a\u90e8\u5206\u5f00\u5904\u7406<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A;\nA.randu(5, 10);   \/\/ or:  mat A(5, 10, fill::randu);\n\nmat B;\nB.randu( size(A) );\n\nmat C(5, 10, fill::zeros);\nC.randu();<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
randu() \uff08\u5177\u6709\u6269\u5c55\u529f\u80fd\u7684\u72ec\u7acb\u51fd\u6570\uff09\nrandn() \uff08\u5177\u6709\u6269\u5c55\u529f\u80fd\u7684\u72ec\u7acb\u51fd\u6570\uff09\n.fill()\n.imbue()\n.ones()\n.zeros()\nsize()\nRNG seed setting\n\u7ef4\u57fa\u767e\u79d1\u4e2d\u7684\u5747\u5300\u5206\u5e03\n\u7ef4\u57fa\u767e\u79d1\u4e2d\u7684\u6b63\u6001\u5206\u5e03<\/code><\/pre>\n\n\n\n
.fill( value )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube\u3001field \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5c06\u5143\u7d20\u8bbe\u7f6e\u4e3a\u6307\u5b9a\u503c<\/p>\n\n\n\n
\u503c\u7684\u7c7b\u578b\u5fc5\u987b\u4e0e\u5bb9\u5668\u5bf9\u8c61\u4f7f\u7528\u7684\u5143\u7d20\u7c7b\u578b\u5339\u914d\uff08\u4f8b\u5982\uff0c\u5bf9\u4e8e mat\uff0c\u7c7b\u578b\u4e3a double)<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A(5, 6);\n\nA.fill(123.0);   \/\/ or:  mat A(5, 6, fill::value(123.0));<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\uff1a\u8981\u5728\u77e9\u9635\u6784\u9020\u671f\u95f4\u5c06\u6240\u6709\u5143\u7d20\u8bbe\u7f6e\u4e3a\u96f6\uff0c\u8bf7\u4f7f\u7528\u4ee5\u4e0b\u66f4\u7d27\u51d1\u7684\u5f62\u5f0f\uff1a
mat A(5, 6, fill::zeros);<\/code><\/p>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.imbue()\n.ones()\n.zeros()\n.randu() & .randn()\n.replace()\n\u5e38\u91cf (pi, nan, inf, ...)<\/code><\/pre>\n\n\n\n
.imbue( functor )<\/h1>\n\n\n\n
.imbue( lambda_function )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row \u548c Cube \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u4f7f\u7528\u51fd\u5b50\u6216 lambda \u51fd\u6570\u63d0\u4f9b\u7684\u503c\u586b\u5145\uff08\u586b\u5145\uff09<\/p>\n\n\n\n
\u5bf9\u4e8e\u77e9\u9635\uff0c\u586b\u5145\u662f\u9010\u5217\u5b8c\u6210\u7684\uff08\u5373\u586b\u5145\u7b2c 0 \u5217\uff0c\u7136\u540e\u586b\u5145\u7b2c 1 \u5217\uff0c\u2026<\/p>\n\n\n\n
\u5bf9\u4e8e\u7acb\u65b9\u4f53\uff0c\u586b\u5145\u662f\u9010\u7247\u5b8c\u6210\u7684\uff0c\u6bcf\u4e2a\u5207\u7247\u90fd\u88ab\u89c6\u4e3a\u4e00\u4e2a\u57fa\u8d28<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
std::mt19937 engine;  \/\/ Mersenne twister random number engine\n\nstd::uniform_real_distribution<double> distr(0.0, 1.0);\n\nmat A(4, 5, fill::none);\n\nA.imbue( [&]() { return distr(engine); } );<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.fill()\n.transform()\n\u5143\u7d20\u8bbf\u95ee\n\u7ef4\u57fa\u767e\u79d1\u7684\u51fd\u6570\u5bf9\u8c61\n\u7ef4\u57fa\u767e\u79d1\u7684C++11\u4e2alambda\u51fd\u6570\ncprogramming.com \u5904\u7684 lambda \u51fd\u6570<\/code><\/pre>\n\n\n\n
.clean( threshold )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube \u548c SpMat \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5bf9\u4e8e\u5177\u6709\u975e\u590d\u6742\u5143\u7d20\u7684\u5bf9\u8c61\uff1a\u6bcf\u4e2a\u5177\u6709\u7edd\u5bf9\u503c\u2264\u9608\u503c\u7684\u5143\u7d20\u90fd\u66ff\u6362\u4e3a\u96f6<\/p>\n\n\n\n
\u5bf9\u4e8e\u5177\u6709\u590d\u6742\u5143\u7d20\u7684\u5bf9\u8c61\uff1a\u5bf9\u4e8e\u6bcf\u4e2a\u5143\u7d20\uff0c\u5177\u6709\u7edd\u5bf9\u503c\u2264\u9608\u503c\u7684\u6bcf\u4e2a\u5206\u91cf\uff08\u5b9e\u6570\u548c\u865a\u6570\uff09\u90fd\u66ff\u6362\u4e3a\u96f6<\/p>\n\n\n\n
\u53ef\u7528\u4e8e\u7a00\u758f\u5316\u77e9\u9635\uff0c\u5373\u5bf9\u5c0f\u5e45\u5ea6\u503c\u7684\u503c\u8fdb\u884c\u5f52\u96f6<\/p>\n\n\n\n
\u6ce8\u610f\uff1a\u82e5\u8981\u663e\u5f0f\u4ece\u5bc6\u96c6\u5b58\u50a8\u8f6c\u6362\u4e3a\u7a00\u758f\u5b58\u50a8\uff0c\u8bf7\u4f7f\u7528 SpMat \u7c7b<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
sp_mat A;\n\nA.sprandu(1000, 1000, 0.01);\n\nA(12,34) =  datum::eps;\nA(56,78) = -datum::eps;\n\nA.clean(datum::eps);<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.replace()\n.clamp()\n.transform()\n.is_zero()\n.zeros()\nnonzeros()\ndatum::eps<\/code><\/pre>\n\n\n\n
.replace( old_value, new_value )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube \u548c SpMat \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5bf9\u4e8e\u6240\u6709\u7b49\u4e8e old_value \u7684\u5143\u7d20\uff0c\u8bf7\u5c06\u5b83\u4eec\u8bbe\u7f6e\u4e3a new_value<\/p>\n\n\n\n
old_value\u548cnew_value\u7684\u7c7b\u578b\u5fc5\u987b\u4e0e\u5bb9\u5668\u5bf9\u8c61\u4f7f\u7528\u7684\u5143\u7d20\u7c7b\u578b\u5339\u914d\uff08\u4f8b\u5982\uff0c\u5bf9\u4e8e mat\uff0c\u7c7b\u578b\u4e3a double)<\/p>\n\n\n\n
\u8b66\u544a\uff1a
\u6d6e\u70b9\u6570\uff08\u6d6e\u70b9\u6570\u548c\u53cc\u7cbe\u5ea6\u6570\uff09\u662f\u8fd1\u4f3c\u503c\uff0c\u56e0\u4e3a\u5b83\u4eec\u7684\u7cbe\u5ea6\u5fc5\u7136\u6709\u9650
\u5bf9\u4e8e\u7a00\u758f\u77e9\u9635 \uff08SpMat\uff09\uff0c\u5f53 old_value = 0 \u65f6\u4e0d\u8fdb\u884c\u66ff\u6362<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A(5, 6, fill::randu);\n\nA.diag().fill(datum::nan);\n\nA.replace(datum::nan, 0);  \/\/ replace each NaN with 0<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.transform()\n.for_each()\n.clean()\n.clamp()\n.fill()\n.has_nan()\n.has_inf()\nfind()\n\u67e5\u627e\uff08\uff09\n\u5173\u7cfb\u8fd0\u7b97\u7b26\n\u5e38\u91cf (pi, nan, inf, ...)<\/code><\/pre>\n\n\n\n
.clamp( min_value, max_value )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube \u548c SpMat \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5c06\u6bcf\u4e2a\u5143\u7d20\u5939\u7d27\u5230 [min_val\uff0c max_val] \u533a\u95f4;
\u4efb\u4f55\u4f4e\u4e8e min_val \u7684\u503c\u90fd\u5c06\u8bbe\u7f6e\u4e3a min_val\uff0c\u4efb\u4f55\u9ad8\u4e8e max_val \u7684\u503c\u90fd\u5c06\u8bbe\u7f6e\u4e3a max_val<\/p>\n\n\n\n
\u5bf9\u4e8e\u590d\u6742\u5143\u7d20\uff0c\u5b9e\u90e8\u548c\u865a\u90e8\u5206\u522b\u5939\u7d27<\/p>\n\n\n\n
\u5bf9\u4e8e\u7a00\u758f\u77e9\u9635\uff0c\u94b3\u4f4d\u4ec5\u5e94\u7528\u4e8e\u975e\u96f6\u5355\u5143<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A(5, 6, fill::randu);\n\nA.clamp(0.2, 0.8);<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.replace()\n.clean()\n.transform()\n.for_each()\nclamp() \uff08\u72ec\u7acb\u51fd\u6570\uff09\n\u5173\u7cfb\u8fd0\u7b97\u7b26<\/code><\/pre>\n\n\n\n
.transform( functor )<\/h1>\n\n\n\n
.transform( lambda_function )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube \u548c SpMat \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u4f7f\u7528\u51fd\u5b50\u6216 lambda \u51fd\u6570\u8f6c\u6362\u6bcf\u4e2a\u5143\u7d20<\/p>\n\n\n\n
\u5bf9\u4e8e\u5bc6\u96c6\u77e9\u9635\uff0c\u6240\u6709\u5143\u7d20\u7684\u8f6c\u6362\u90fd\u662f\u9010\u5217\u5b8c\u6210\u7684<\/p>\n\n\n\n
\u5bf9\u4e8e\u7a00\u758f\u77e9\u9635\uff0c\u5bf9\u975e\u96f6\u5143\u7d20\u8fdb\u884c\u9010\u5217\u8f6c\u6362<\/p>\n\n\n\n
\u5bf9\u4e8e\u7acb\u65b9\u4f53\uff0c\u8f6c\u6362\u662f\u9010\u4e2a\u5207\u7247\u5b8c\u6210\u7684\uff0c\u6bcf\u4e2a\u5207\u7247\u90fd\u88ab\u89c6\u4e3a\u4e00\u4e2a\u77e9\u9635<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A(4, 5, fill::ones);\n\n\/\/ add 123 to every element\nA.transform( [](double val) { return (val + 123.0); } );<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.for_each()\n.replace()\n.imbue()\n.clean()\n.clamp()\n\u5143\u7d20\u8bbf\u95ee\n\u91cd\u8f7d\u8fd0\u7b97\u7b26\n\u5176\u4ed6\u5143\u7d20\u51fd\u6570\uff08exp\u3001log\u3001sqrt\u3001square\u3001round \u7b49\uff09\n\u7ef4\u57fa\u767e\u79d1\u7684\u51fd\u6570\u5bf9\u8c61\n\u7ef4\u57fa\u767e\u79d1\u7684C++11 lambda\u51fd\u6570\ncprogramming.com \u5904\u7684 lambda \u51fd\u6570<\/code><\/pre>\n\n\n\n
.for_each( functor )<\/h1>\n\n\n\n
.for_each( lambda_function )<\/h1>\n\n\n\n
Mat\u3001Col\u3001Row\u3001Cube\u3001SpMat \u548c field \u7684\u6210\u5458\u51fd\u6570<\/p>\n\n\n\n
\u5bf9\u4e8e\u6bcf\u4e2a\u5143\u7d20\uff0c\u5c06\u5176\u5f15\u7528\u4f20\u9012\u7ed9\u51fd\u5b50\u6216 lambda \u51fd\u6570<\/p>\n\n\n\n
\u5bf9\u4e8e\u5bc6\u96c6\u77e9\u9635\u548c\u5b57\u6bb5\uff0c\u6240\u6709\u5143\u7d20\u7684\u5904\u7406\u90fd\u662f\u9010\u5217\u5b8c\u6210\u7684<\/p>\n\n\n\n
\u5bf9\u4e8e\u7a00\u758f\u77e9\u9635\uff0c\u5bf9\u975e\u96f6\u5143\u7d20\u8fdb\u884c\u9010\u5217\u5904\u7406<\/p>\n\n\n\n
\u5bf9\u4e8e\u7acb\u65b9\u4f53\uff0c\u5904\u7406\u662f\u9010\u4e2a\u5207\u7247\u5b8c\u6210\u7684\uff0c\u6bcf\u4e2a\u5207\u7247\u90fd\u88ab\u89c6\u4e3a\u4e00\u4e2a\u77e9\u9635<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
\/\/ add 123 to each element in a dense matrix\n\nmat A(4, 5, fill::ones);\n\nA.for_each( [](mat::elem_type& val) { val += 123.0; } );  \/\/ NOTE: the '&' is crucial!\n\n\n\/\/ add 123 to each non-zero element in a sparse matrix\n\nsp_mat S; S.sprandu(1000, 2000, 0.1);\n\nS.for_each( [](sp_mat::elem_type& val) { val += 123.0; } );  \/\/ NOTE: the '&' is crucial!\n\n\n\/\/ set the size of all matrices in field F\n\nfield<mat> F(2,3);\n\nF.for_each( [](mat& X) { X.zeros(4,5); } );  \/\/ NOTE: the '&' is crucial!<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.transform()\n.replace()\n.each_col() & .each_row()\n.each_slice()\n\u5143\u7d20\u8bbf\u95ee\n\u5176\u4ed6\u5143\u7d20\u51fd\u6570\uff08exp\u3001log\u3001sqrt\u3001square\u3001round \u7b49\uff09\n\u7ef4\u57fa\u767e\u79d1\u7684\u51fd\u6570\u5bf9\u8c61\n\u7ef4\u57fa\u767e\u79d1\u7684C++11\u4e2alambda\u51fd\u6570\ncprogramming.com \u5904\u7684 lambda \u51fd\u6570<\/code><\/pre>\n\n\n\n
.set_size( n_elem ) (Col, Row, field\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.set_size( n_rows, n_cols ) (Mat, SpMat, field\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.set_size( n_rows, n_cols, n_slices ) (Cube \u548c field\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
.set_size( size(X) ) (Mat, Col, Row, Cube, SpMat, field\u7684\u6210\u5458\u51fd\u6570)<\/h1>\n\n\n\n
\u66f4\u6539\u5bf9\u8c61\u7684\u5927\u5c0f\uff0c\u800c\u4e0d\u663e\u5f0f\u4fdd\u7559\u6570\u636e\uff0c\u4e5f\u4e0d\u521d\u59cb\u5316\u5143\u7d20\uff08\u5373\u5143\u7d20\u53ef\u80fd\u5305\u542b\u5783\u573e\u503c\uff0c\u5305\u62ec NaN\uff09<\/p>\n\n\n\n
\u8981\u5728\u66f4\u6539\u5927\u5c0f\u65f6\u5c06\u5143\u7d20\u521d\u59cb\u5316\u4e3a\u96f6\uff0c\u8bf7\u6539\u7528 .zeros\uff08\uff09<\/p>\n\n\n\n
\u8981\u5728\u66f4\u6539\u5927\u5c0f\u65f6\u663e\u5f0f\u4fdd\u7559\u6570\u636e\uff0c\u8bf7\u6539\u7528 .reshape\uff08\uff09 \u6216 .resize\uff08\uff09;
\u6ce8\u610f\uff1a.reshape\uff08\uff09 \u548c .resize\uff08\uff09 \u6bd4 .set_size\uff08\uff09 \u6162\u5f97\u591a<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
mat A;\nA.set_size(5, 10);      \/\/ or:  mat A(5, 10, fill::none);\n\nmat B;\nB.set_size( size(A) );  \/\/ or:  mat B(size(A), fill::none);\n\nvec v;\nv.set_size(100);        \/\/ or:  vec v(100, fill::none);<\/code><\/pre>\n\n\n\n
\u53e6\u8bf7\u53c2\u9605\uff1a<\/p>\n\n\n\n
.reset()\n.copy_size()\n.reshape()\n.resize()\n.zeros()\nsize()<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
@[toc] \u5c5e\u6027 \u53d8\u91cf\u7684\u7c7b\u578b\u4e3a uword \u53d8\u91cf\u662f\u53ea\u8bfb\u7684; \u8981\u66f4\u6539\u5927\u5c0f\uff0c\u8bf7\u4f7f\u7528 .set_size\uff08\uff09\u3001.c […]<\/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-46","post","type-post","status-publish","format-standard","hentry","category-algorithm"],"_links":{"self":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/46","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=46"}],"version-history":[{"count":2,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions"}],"predecessor-version":[{"id":50,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=\/wp\/v2\/posts\/46\/revisions\/50"}],"wp:attachment":[{"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=46"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=46"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chaixiangyu.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=46"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}