std::slice

<metanoindex/>

 

C++

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In fase di compilazione aritmetica razionale (C++11)

Generici operazioni numeriche Original: Generic numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

iota (C++11)

accumulate

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std::valarray

Membri funzioni Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+ valarray::operator- valarray::operator~ valarray::operator! valarray::operator+= valarray::operator-= valarray::operator*= valarray::operator/= valarray::operator%= valarray::operator&= valarray::operator|= valarray::operator^= valarray::operator<<= valarray::operator>>=
Non membri funzioni Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
swap (C++11) begin (C++11) end (C++11) abs exp log log10 pow sqrt sin cos tan asin acos atan atan2 sinh cosh tanh	operator* operator/ operator% operator+ operator- operator^ None operator& operator| operator<< operator>> operator&& operator None operator== operator!= operator< operator> operator<= operator>=
Helper classi Original: Helper classes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
slice_array gslice_array indirect_array	slice gslice mask_array

 

<tbody> </tbody>

Elemento definito nell'header <valarray>
class slice;

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[].

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Membri funzioni

(costruttore)	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)
start	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)
size	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)
stride	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.

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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';
}

Output:

Trace of the matrix (1,2,3) (4,5,6) (7,8,9) is 15

Vedi anche

operator[]	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)
gslice	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)
slice_array	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)