$PROBLEM MIX VS XFORM
$INPUT ID, AMT, TIME, WT, AGE, DV, EVID, MDV, REA
$DATA DATA1.TXT (9E12.0) ;NOOPEN REWIND

$SUBROUTINES ADVAN2
$PK
   KA=THETA(1)*EXP(ETA(1))
  
   K=THETA(2)*EXP(ETA(2))
     
   S2=THETA(3)*WT
  
$THETA
(0,1)  ;KA
(0,.1) ;K
(0,.4) ;VD
$OMEGA BLOCK(1) .25 ;INTER-SUBJECT VARIATION KA
$OMEGA BLOCK(1) .05 ;INTER-SUBJECT VARIATION K


$ERROR

 Y=F*(1+EPS(1))

$SIGMA .01         ;PROPORTIONAL ERROR

$ESTIMATION MAXEVALS=9000 PRINT=1 METHOD=1 INTERACTION

$COV

$TABLE ONEHEADER NOPRINT FIRSTONLY ID ETA1 ETA2 REA FILE=T1A.TXT
;