std::slice
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Defined in header <valarray>
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class slice; |
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std::slice
est le sélecteur de classe qui identifie un sous-ensemble de std::valarray similaire à tranche BLAS. Un objet de type de std::slice
contient trois valeurs: l'index de départ, le pas et le nombre total de valeurs dans le sous-ensemble. Objets de std::slice
type peut être utilisé comme index avec 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.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
maria 123456
[modifier] Fonctions membres
construit une tranche
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. maria
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accède au début de la tranche
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. maria
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accède à la taille de la tranche
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. maria
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accède à la foulée de la tranche
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. maria
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[modifier] Exemple
Barebones classe Matrix valarray soutenu avec une fonction tracer calcul .
Original:
Barebones valarray-backed Matrix class with a tracer calculating function.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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maria
123456#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'; }
Résultat :
Trace of the matrix (1,2,3) (4,5,6) (7,8,9) is 15
[modifier] Voir aussi
get / set élément valarray, tranche, ou un masque
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. maria
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tranche généralisée d'une valarray: indice de départ, un ensemble de longueurs, jeu de progrès
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. maria
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procuration d'un sous-ensemble d'un valarray après l'application d'une tranche
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. maria
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