单行初始化器的Boost.MultiArray的 [英] One-line initialiser for Boost.MultiArray

问题描述

我有一个n维Boost.MultiArray的我初始化如下：

I have a n-dimensional Boost.MultiArray I initialize as follows:

const int n=3, size=4; //# of dimensions and size of one dimension
boost::multi_array<char,n> arr;
boost::array<size_t,n> extents; //size of each dimension
extents.assign(size); //assign size to each dimension -> {{4, 4, 4}}
arr.resize(extents);

所以我有4行code，以获得MultiArray的，但我想这样做在同一行。
是否有产生的MultiArray与n维各有尺寸长度的任何简单的方式（这样我就可以写 ARR（samevaluearray（N，大小）））或我错过了一个方便的构造MultiArray的？

So I have 4 lines of code to get the MultiArray, but I'd like to do it in one line. Is there any simple way to generate an MultiArray with n dimensions each having size length (so I can write arr(samevaluearray(n,size))) or did I miss a handy constructor for MultiArray?

编辑：的应该不依赖于n的一定价值的工作，即 ARR（{{大小，大小}} 只会工作为 N = 2 。

It should work without depending on a certain value of n, i.e. arr({{size,size}} would only work for n=2.

由于它可能不是很清楚：的boost :: multi_array的＆LT;焦炭，N＆GT;（升压::程度[4] [4] [4]）正确初始化型4x4x4阵列，但每次 N 源$ C ​​$ C变更，每次初始化需要手工进行更新，所以它不是一个选项。

Since it may not be clear: boost::multi_array<char,n>(boost::extents[4][4][4]) correctly initializes a 4x4x4-array, but every time n is changed in the sourcecode, every initialization has to be updated by hand, so it's not an option.

推荐答案

原来，的std ::矢量有一个构造函数，即构造一个向量重复一个恒定值n次，所以一个可能的解决方案是这样的：

Turns out, std::vector has a constructor, that constructs a vector with a constant value repeated n times, so a possible solution looks like this:

const int n=2, size=4; //# of dimensions and size of one dimension
boost::multi_array<char,n> arr(std::vector<size_t>(n,size));

这与初始化每个维度的大小设置为大小N维的multi_array。

This initializes a n-dimensional multi_array with each dimension's size set to size.

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