std::slice
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| Definido no cabeçalho <valarray>
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| class slice; |
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std::slice é a classe selector que identifica um subconjunto de std::valarray semelhante a fatia BLAS. Um objecto da std::slice tipo prende três valores: o índice de partida, o passo, e o número total de valores no subconjunto. Objectos de std::slice tipo podem ser usados como índices com operator[] valarray de.Original:
std::slice is the selector class that identifies a subset of std::valarray similar to BLAS slice. An object of type std::slice holds three values: the starting index, the stride, and the total number of values in the subset. Objects of type std::slice can be used as indexes with valarray's operator[].The text has been machine-translated via Google Translate.
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[editar] Funções de membro
| constrói uma fatia Original: constructs a slice The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) | |
| acede ao início da fatia Original: accesses the start of the slice The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) | |
| acede ao tamanho da fatia Original: accesses the size of the slice The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) | |
| acessa o tranco da fatia Original: accesses the stride of the slice The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) | |
[editar] Exemplo
Barebones classe Matrix valarray apoiado com uma função traçar cálculo .
Original:
Barebones valarray-backed Matrix class with a traçar calculating function.
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#include <iostream> #include <valarray> class Matrix { std::valarray<int> data; int dim; public: Matrix(int r, int c) : data(r*c), dim(c) {} int& operator()(int r, int c) {return data[r*dim + c];} int trace() const { return data[std::slice(0, dim, dim+1)].sum(); } }; int main() { Matrix m(3,3); int n = 0; for(int r=0; r<3; ++r) for(int c=0; c<3; ++c) m(r, c) = ++n; std::cout << "Trace of the matrix (1,2,3) (4,5,6) (7,8,9) is " << m.trace() << '\n'; }
Saída:
Trace of the matrix (1,2,3) (4,5,6) (7,8,9) is 15
[editar] Veja também
| get / set elemento valarray, uma fatia ou máscara Original: get/set valarray element, slice, or mask The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) | |
| fatia generalizada de uma valarray: índice inicial, conjunto de comprimentos, conjunto de passos Original: generalized slice of a valarray: starting index, set of lengths, set of strides The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe) | |
| proxy para um subconjunto de uma valarray após a aplicação de uma fatia Original: proxy to a subset of a valarray after applying a slice The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de classe) | |
