M1 = "numeric", #order-1 moment (vector size d)
M2 = "numeric", #M2 easier to process as a vector
M3 = "numeric", #M3 easier to process as a vector
M1 = "numeric", #order-1 moment (vector size d)
M2 = "numeric", #M2 easier to process as a vector
M3 = "numeric", #M3 easier to process as a vector