COEFFICIENT MATRIX IS ALGORITHMICALLY SINGULAR
From: Partha Nandy partha.nandy@bms.com
Subject: [NMusers] COEFFICIENT MATRIX IS ALGORITHMICALLY SINGULAR
Date: Wed, August 11, 2004 12:02 pm
Hi All,
While executing the following code, I am getting the Error Message. Can
anyone tell me what it means and how can it be avoided?
> OCCURS DURING SEARCH FOR ETA AT INITIAL VALUE, ETA=0
>
> NUMERICAL DIFFICULTIES OBTAINING THE SOLUTION.
>
> THE COEFFICIENT MATRIX IS ALGORITHMICALLY SINGULAR.
I appreciate your help
Kind Regards,
Partha
(Partha Nandy)
Clinical Discovery-BMS
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The CTL file:
$PROBLEM
$INPUT C TIME DV SUBJ ID AMT TYPE EVID MDV CMT RATE TAMT AGE HT WT SA
SEX RCE
$DATA C:\ IGNORE=C
$SUBROUTINES ADVAN5
$MODEL COMP=(DEPOT1) COMP=(CENTERAL,DEFOBS)
$PK
CLS=THETA(1)*EXP(ETA(1)) ; Induced Clearance
CLI=THETA(2)*EXP(ETA(2)) ; Baseline Clearance
KOUT=THETA(3)*EXP(ETA(3)) ;Turnover rate
LAG=THETA(4)*EXP(ETA(4))
NEWT=TIME-LAG
IF (NEWT.LE.0) NEWT=0
CL2=CLS-((CLS-CLI)*EXP(-KOUT*NEWT))
TVV2=THETA(5)
V2=THETA(5)*EXP(ETA(5))
D1=THETA(6) ;Duration of zero-order input
F1=THETA(7) ; Bioavaialbility factor
K20=CL2/V2
S2=V2/1000
$ERROR
FX=0
IF(F.EQ.0) FX=1
W=F+FX
Y=F*(1+ERR(1))+ERR(2)
IPRE=F
IRES=DV-IPRE
IWRE=IRES/W
$THETA
(0,100) ;THETA-1,CL
(0,500) ;THETA-2,CL
(0,300) ;THETA-3,CL
(6,172) ;lag
(0,800) ;V
(0,10) ;D1
(0,0.5,1) ;F1
$OMEGA .5 .5 .5 .4 0.5
$SIGMA 0.2 5
$ESTIMATION MAXEVAL=9999 PRINT=5 NOABORT METHOD=1 INTERACTION
$COV
$TABLE ONEHEADER NOPRINT FILE=C:\*.tab
ID TIME DV SUBJ AMT CL2
V2 ETA(1) ETA(2) ETA(3) IPRE K20
D1 F1
$SCATTER PRED VS DV UNIT BY CMT
$SCATTER RES WRES VS PRED TIME ORD0 BY CMT
$SCAT PRED DV VS TIME BY CMT
$SCATTER IPRE VS DV UNIT BY CMT