HI, sorry for many Qs posted here.. BIG THANKS to all the replies.. I have another Q for "prmat": I have a 12 x 12 data points, i want to increase the granularity to 0.1x0.1, so I use the following function call: data.pr <- prmat(data.kr, 1, 12, 1, 12, 120) I would expect the data points is 121 x 121, and at 1, 1.1, 1.2, 1.3, ..., 11.9, 12 etc.. The result from the above prmat function call is 121x121 data points, however, they are NOT at 1, 1.1, 1.2.. BUT at 1.000000 1.091667 1.183333 1.275000......11.908333 12.000000 Could anyone enlighten me If i want to get estimated value at 1, 1.1, 1.2, 1.3..., what i should do? many thanks, yan