3.5 Selecting and Ordering

Selecting a subset of elements in one or several dimension results in a datacube of the same dimension with fewer tuples. This operation can be neatly integrated into a visualisation tool of datacube. Another similar operation is ordering: The elements in one or several dimension are sorted along a criterion. For example, a distance matrix can be sorted in the order of the distance (global sorting) to get the 5 shortest distance in the matrix, but one could also sort it along one dimension (dimensional sorting), to get the 5 closest neighbors of each location. This may be interesting in a heuristic to find a good TSP tour.