MACC2 Encoding

These results can be seen, from a mathematical point of view, as a set of n quantitative-continuous variables, each representing a range of distances. It is possible to represent these values in a graphic like the one represented in Fig. 6.4, which is called a correlogram , in which the distances are represented on the horizontal axis and the scaled product of energies on the vertical axis. 

The first characteristic of this geometry representation that must be emphasized is that it is completely alignment independent, since the values assigned to every variable depend only on the mutual distance of the nodes and not on the position of the nodes in space. Therefore, if we carry out this analysis for a series of molecules not aligned in space, the variables obtained for every compound do nevertheless have the same meaning and the values obtained can be combined to build a consistent descriptor matrix, without the need to align or otherwise superimpose their structures. 

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