std::gslice

 

C++

Suporte ao Compilador

Freestanding and hosted

Linguagem

Headers da Biblioteca Standard

Requerimentos nomeados

Feature test macros (C++20)

Biblioteca de suporte de língua

Biblioteca de conceitos(C++20)

Biblioteca de diagnósticos

Biblioteca de utilitários em geral

Biblioteca de strings

Biblioteca de containers

Ranges library(C++20)

Biblioteca de iteradores

Biblioteca de algorítmos

Biblioteca numérica

Biblioteca de localizações

Biblioteca de input/output

Biblioteca de sistema de arquivo(C++17)

Biblioteca de expressões regulares(C++11)

Biblioteca de operações atômicas(C++11)

Biblioteca de suporte de thread(C++11)

Especificações Técnicas

Índice de symbolos

Bibliotecas externas

 

Biblioteca numéricos

Funções matemáticas comuns

De ponto flutuante ambiente

Números complexos

Matrizes numéricas

Pseudo-aleatório de geração de números

Tempo de compilação aritmética racional(C++11)

Genéricos operações numéricas 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

inner_product

adjacent_difference

partial_sum

 

std::valarray

Funções de membro 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>>=
Não-membros funções 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>=
Classes auxiliares 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

 

Definido no cabeçalho <valarray>
class gslice;

std::gslice é a classe selector que identifica um subconjunto de índices std::valarray definidos por um conjunto de níveis múltiplos de passos e tamanhos. Objectos de std::gslice tipo podem ser usados ​​como índices com operator[] valarray para seleccionar, por exemplo, as colunas de uma matriz multidimensional representada como uma valarray.

Original:

std::gslice is the selector class that identifies a subset of std::valarray indices defined by a multi-level set of strides and sizes. Objects of type std::gslice can be used as indices with valarray's operator[] to select, for example, columns of a multidimensional array represented as a valarray.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Dada a s valor inicial, de uma lista de passos i
j e uma lista de tamanhos d
j, um std::gslice construídos a partir destes valores selecciona o conjunto de índices k
j=s+Σ
j(i
jd
j).

Original:

Given the starting value s, a list of strides i
j and a list of sizes d
j, a std::gslice constructed from these values selects the set of indices k
j=s+Σ
j(i
jd
j).

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Por exemplo, um GSlice com 3 índice inicial, passos {19,4,1} e comprimentos {2,4,3} gera o seguinte conjunto de índices:

Original:

For example, a gslice with starting index 3, strides {19,4,1} and lengths {2,4,3} generates the following set of indices:

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

3+0*19+0*4+0*1=3,
3+0*19+0*4+1*1=4,
3+0*19+0*4+2*1=5,
3+0*19+1*4+0*1=7,
3+0*19+1*4+1*1=8,
...
3+1*19+3*4+2*1=36

É possível construir objectos std::gslice que alguns índices seleccionar mais do que uma vez: o exemplo acima, se utilizado o {1,1,1} passos, os índices teria sido {3, 4, 5, 4, 5, 6, ...} . Gslices só podem ser usados ​​como argumentos para a versão de const std::valarray::operator[], caso contrário, o comportamento é indefinido.

Original:

It is possible to construct std::gslice objects that select some indices more than once: if the above example used the strides {1,1,1} , the indices would have been {3, 4, 5, 4, 5, 6, ...} . Such gslices may only be used as arguments to the const version of std::valarray::operator[], otherwise the behavior is undefined.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Funções de membro

(constructor)	constrói um GSlice Original: constructs a gslice 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)
start	acede ao início do GSlice Original: accesses the start of the gslice 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)
stride	acessa a matriz de passos do GSlice Original: accesses the array of strides of the gslice 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)
size	acessa a matriz de sizees do GSlice Original: accesses the array of sizees of the gslice 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)

Exemplo

demonstra a utilização de gslices para tratar colunas de uma matriz em 3D

Original:

demonstrates the use of gslices to address columns of a 3D array

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

#include <iostream>#include <valarray>void test_print(std::valarray<int>& v, int rows, int cols, int planes){for(int r=0; r<rows;++r){for(int c=0; c<cols;++c){for(int z=0; z<planes;++z)std::cout<< v[r*cols*planes + c*planes + z]<<' ';std::cout<<'\n';}std::cout<<'\n';}}int main(){std::valarray<int> v =// 3d array: 2 x 4 x 3 elements{111,112,113 , 121,122,123 , 131,132,133 , 141,142,143, 211,212,213 , 221,222,223 , 231,232,233 , 241,242,243};// int ar3d[2][4][3]std::cout<<"Initial 2x4x3 array:\n"; test_print(v, 2, 4, 3);   // update every value in the first columns of both planes v[std::gslice(0, {2, 4}, {4*3, 3})]=1;// two level one strides of 12 elements// then four level two strides of 3 elements   // subtract the third column from the second column in the 1st plane v[std::gslice(1, {1, 4}, {4*3, 3})]-= v[std::gslice(2, {1, 4}, {4*3, 3})];   std::cout<<"After column operations: \n"; test_print(v, 2, 4, 3);}

Saída:

Initial 2x4x3 array: 111 112 113 121 122 123 131 132 133 141 142 143   211 212 213 221 222 223 231 232 233 241 242 243   After column operations: 1 -1 113 1 -1 123 1 -1 133 1 -1 143   1 212 213 1 222 223 1 232 233 1 242 243

Veja também

operator[]	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)
slice	BLAS-como fatia de um valarray: índice inicial, comprimento da passada Original: BLAS-like slice of a valarray: starting index, length, stride The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe)
gslice_array	proxy para um subconjunto de uma valarray após a aplicação de uma GSlice Original: proxy to a subset of a valarray after applying a gslice 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)