Computes the unscaled covariance matrix for an SSM object for a given length parameter.
compute.covariance(ssm, r)An SSM object.
A number. The length parameter used by the correlation function.
The unscaled covariance matrix.
The covariance matrix uses the correlation function specified by the SSM slot
type. "matern32" uses a Matern 3/2 correlation while
"exp" uses a squared exponential.