hi William and Atul, NONMEM TOLD ME " data record error message from pred: run terminated because of errors in data records"
so I thought there may be something woring with ADDL column in my data file so, I changed it to: #ID TIME DV AMT ADDL II MDV 102 0 0 60 31 48 1 102 0.5 205 0 0 0 0 102 1 305 0 0 0 0 102 2 283 0 0 0 0 102 4 134 0 0 0 0 102 6 78.8 0 0 0 0 102 8 51.5 0 0 0 0 102 12 17.6 0 0 0 0 102 24 2.16 0 0 0 0 102 48 0 60 30 12 1 102 192 704 0 0 0 0 102 360 585 0 0 0 0 102 360.5 782 0 0 0 0 102 361 1070 0 0 0 0 102 362 1460 0 0 0 0 102 364 1270 0 0 0 0 102 366 965 0 0 0 0 102 368 652 0 0 0 0 102 372 433 0 0 0 0 then it still was not runing due to the same error massage. I tried different initial values for PK parameters, but it does not work. by the way,I am using NONMEM V, and 1035 observations from 65 subjects is available for the analysis. Thanks so much for your input! Yuyan
