std::slice
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| Déclaré dans l'en-tête <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.
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[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. (fonction membre publique) | |
| 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. (fonction membre publique) | |
| 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. (fonction membre publique) | |
| 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. (fonction membre publique) | |
[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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#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. (fonction membre publique) | |
| 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. (classe) | |
| 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. (classe générique) | |
