<metanoindex/>
<tbody> </tbody>| Elemento definito nell'header <valarray>
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class slice; |
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std::slice è la classe selettore che identifica un sottoinsieme di std::valarray simile alla slice BLAS. Un oggetto di tipo std::slice contiene tre valori: l'indice di partenza, il passo, e il numero totale di valori nel sottoinsieme. Gli oggetti di std::slice tipo possono essere utilizzati come indici con operator[] valarray di.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.
Membri funzioni
costruisce una fetta 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. (metodo pubblico) | |
accede l'inizio della fetta 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. (metodo pubblico) | |
accede alla dimensione della slice 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. (metodo pubblico) | |
accede al passo della fetta 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. (metodo pubblico) | |
Esempio
Barebones valarray-backed classe Matrix con una funzione di calcolo traccia .
Original:
Barebones valarray-backed Matrix class with a traccia calculating function.
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.
#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';
}
Output:
Trace of the matrix (1,2,3) (4,5,6) (7,8,9) is 15
Vedi anche
get / set elemento valarray, fetta, o maschera 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. (metodo pubblico) | |
fetta generalizzata di un valarray: indice iniziale, set di lunghezze, serie di passi 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 per un sottoinsieme di un valarray dopo l'applicazione di una fetta 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 template) | |