The matrix Lambda is half the semivariogram matrix. The function
returns the conditional covariance with respect to entries in co,
restricted to the subA rows and the subB columns.
Lambda2cov(Lambda, co, subA, subB)Negative definite matrix for the Huesler--Reiss model
vector of integer with conditioning sites
vector of integers with sub-entries (not in co) for rows
vector of integers with sub-entries (not in co) for columns. If missing, default to subA.