Most efficient option for build 3D structures using Eigen matrices

Question

I need a 3D matrix/array structure on my code, and right now I\'m relying on Eigen for both my matrices and vectors.

Right now I am creating a 3D structure using

Answer 1

An alternative is to create a very large chunk of memory ones, and maps Eigen matrices from it:

double* data = new double(60*60 * 60*60*60);

Map Mijk(data+60*(60*(60*k)+j)+i), 60, 60);

At this stage you can use Mijk like a MatrixXd object. However, since this not a MatrixXd type, if you want to pass it to a function, your function must either:

• be of the form foo(Map mat)
• be a template function: template void foo(const MatrixBase& mat)
• take a Ref object which can handle both Map<> and Matrix<> objects without being a template function and without copies. (doc)