Creates a configuration object for computing cosine dissimilarity
(also known as spectral angle mapper). Pass the result to
dissimilarity() to compute the dissimilarity matrix.
The cosine dissimilarity between two observations x_ix_i and
x_jx_j is:
c(x_i, x_j) = ^-1
_k=1^p x_i,k\, x_j,k
_k=1^p x_i,k^2\,
_k=1^p x_j,k^2c(x_i, x_j) = acos(sum_k x_i,k * x_j,k / (sqrt(sum_k x_i,k^2) * sqrt(sum_k x_j,k^2)))
where pp is the number of variables.