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From: Nilesh Timilsina on 14 Oct 2009 17:58
Dear Sas Experts

I am trying to run a individual tree diameter growth model using Proc
Nlmixed. Below is the code i am trying to run. But I always get the message,
"Quadrature accuracy of 0.000100 could not be achieved with 31 points. The
achieved accuracy was 0.00044", if i run the model with method=gauss. If the
same model is used with method=firo i get the message, "Floating point
overflow, termination due to floating point exception. I am new to this non
linear mixed model thing. I would really appreciate the help to solve this
problem

*

proc* *nlmixed* data = test method=firo;

parms a0=*0.1141* a2=-*0.00100* a3=-*0.01453* /*a4=-0.00042 c0=0.1094*/ c1=
*0.002151* log_sd=*0* log_s2u1=*1* log_s2u2=*1
*

z=*0*;

s2 = exp(*2**log_sd);

s2u1=exp(*2**log_s2u1);

s2u2=exp(*2**log_s2u2);

rho = (exp(*2**z)-*1*)/(exp(*2**z)+*1*);

cv1 = rho*exp(log_s2u1+log_s2u2);

b= a0 + (a2+u1)*totht + (a3+u2)*sum_SI;

c= c1*spi2;

pred = (b/(b-c))*(exp(-c*curdbh)-exp(-b*curdbh));

MODEL ldbhgr3 ~ normal(pred, S2);

RANDOM u1 u2 ~ normal([*0*,*0*],[s2u1,cv1,s2u2]) SUBJECT=fk_sdi OUT
=out_Rand;

PREDICT pred out=preds;
*

run*;



Thanking you

Nilesh Timilsina
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