Dear all, I'm trying to fit a dataset with proc model and ordinary differential equations, but somehow it does not work. SAS complains that I don't have the values A1 and A2 in the dataset, but they can't be in the dataset. Any ideas? The dataset and the code is attached below. Many thanks in advance. Thorsten ata step01; INPUT time conc; datalines; 0.1 1.50 0.2 3.20 0.4 4.30 0.6 5.10 0.8 5.40 1 5.20 1.2 5.00 1.4 4.80 2 4.00 3 2.50 4 1.50 5 1.00 6 0.62 7 0.40 8 0.25 10 0.10 run; proc model data=step01; ENDOGENOUS A1 400 A2 0 ; dert.A1 = -ka * A1; dert.A2 = ka * A1 - (CL/V2)*A2; CONC=A2/V2; FIT CONC start=(KA 2.5 CL 20 V2 50) ; run; quit;
... View more