Sorted grids
Sorted grids are a wrapper around the Vector class
that demands that all elements fulfill a certain condition. This condition
is a template the class take as input, which is used to ensure that the elements are sorted.
It is implemented as the class grid_t in the C++ code.
There are only two classes named of the type:
AscendingGridwhich is a grid where every subsequent element must be strictly not less or equal to the previous element.DescendingGridwhich is a grid where every subsequent element must be strictly not greater or equal to the previous element.
The usefulness of these classes is simply that you know that their values are sorted.
The member methods that they provide are a limited subset of the Vector class that do not modify
state of the Vector in any way. Constant iteration (begin and end), size-queries (size and shape),
as well as constant element and ranged access (operator[]).
To create a sorted grid, simply pass a Vector to the constructor or the operator=.
For convenience, grid_t provides a static helper method that can be used to check if your Vector or view thereof is sorted. This method is called:
grid_t<>::is_sorted(vec) and simply returns a boolean value for the state of the vector as a grid. true being sorted and false being not sorted.
Extending a grid
Because we want to ensure that all grids are always sorted properly, the
safest way to extend a grid is to simply copy the values it holds into a
Vector and then modify your new Vector as needed.
The last step is to move then to move your now modified Vector back into the grid.
For cases where you know this will not work well, you can use the extend_grid_t class.
It takes a reference to the grid and exposes the Vector interface
directly. Upon destroying the extend_grid_t object, the grid is checked to ensure the sorting is correct.
Relevant files
The relevant files for the data holding core matpack types are:
matpack/matpack_mdspan_helpers_grid_t.h- thegrid_tandextend_grid_tclasses.