Set signature for pseudo-Euclidean dataset or mapping
B = SETSIG(A,SIG)
Distances in a PE dataset are computed in a special way, see PE_DISTM using the signature of the PE space. This routine stores the signature in the user-field of the dataset, so it can be used by any routine that needs it. The signature is determined during a pseudo-Euclidean mapping, e.g. by PSEM. Datasets applied to such a mapping obtain the signature automatically. The signature is a vector of two elements equal to the numbers of positive and negative eigenvalues found during the process of PE mapping. Their sum should thereby be equal to the dimensionality of the space, i.e. the number of features in A.
Note that V = W*SETSIG converts a pseudo-Euclidean mapping W into a mapping V to the associated space.