Question

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);

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?

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

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.

Answer 1

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));

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