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Hi every one please help me with my problem. I have the model that estimated by proc nlmixed then i need to plot the actual and predicted.   proc import datafile='C:\Users\Abbas Arkawazi\Desktop\test.xlsx' DBMS =xlsx Out=test; run; proc nlmixed data=test;    parms b0= 10 b1=2  b2=.5   b3= 1  a=2 b=1  s=  150 ;    m = b0+(b1*age)+(b2*gender)+(b3*creatin);    y=urea;    if status_u=1 then f=((a*b)*((1-exp(-exp((y-m)/s)))**(a-1))*((1+((exp(exp((y-m)/s))-1)**(a)))**(-(b+1)))) /(s*exp((-a*exp((y-m)/s))-((y-m)/s))) ;    else f= (1+(((1-exp(-exp((y-m)/s)))/(exp(-exp((y-m)/s))))**a))**-b ;    ll=log(f);    model y ~ general(ll); run; please help me to plot the estimated model  thank u very much ... View more

Hello, I am working on fitting nonlinear mixed model to my data using proc nlmixed. My model has four fixed effects & five random effects.  But when I run the program, I get the following warning: WARNING: The final Hessian matrix is full rank but has at least one negative eigenvalue. Second-order optimality condition violated. Please help me solve this problem and guide me to the right way to solve this problem. My code is the following and the data is in the attachment:  proc import datafile='C:\Users\Abbas Arkawazi\Desktop\test.xlsx' DBMS =xlsx Out=test; run; proc nlmixed data=test ; parms b0=1 b1=2 b2=3 b3=4 a=2 b=1 aa=3 bb=1 s=100; m =b0+(b1*age)+(b2*creatin)+(b3*gender); y=urea; if status_u=1 then f=((aa*bb*a*b)/s)*(exp(-b*exp((y-m)/s)))*((1-exp(-b*exp((y-m)/s)))**(a-1))*((((1-exp(-b*exp((y-m)/s)))**a)**(aa-1))/((1-((1-exp(-b*exp((y-m)/s)))**a))**(aa+1)))*((1+((((1-exp(-b*exp((y-m)/s)))**a)/(1-((1-exp(-b*exp((y-m)/s)))**a)))**aa))**(-bb-1)) ; else f= 1-((1+(((1-exp(-b*exp((y-m)/s)))**a)/(1-(1-exp(-b*exp((y-m)/s)))**a))**aa)**-bb) ; ll=log(f); model y ~ general(ll); run;   ... View more

Hello everyone...please help me in how to chose the initial values for the parameters in the proc Nlmixed for the following model with attached data.   proc import datafile='C:\Users\Abbas Arkawazi\Desktop\test.xlsx' DBMS =xlsx Out=test; run; proc nlmixed data=test; parms b0=70 b1=1 b2=8 b3=1 a=2 b=1 s=220; bounds a b > 0; m =b0+(b1*age)+(b2*creatin)+(b3*gender1); y=urea; if status_u=1 then f=((a*b)*((1-exp(-exp((y-m)/s)))**(a-1))*((1+((exp(exp((y-m)/s))-1)**(a)))**(-(b+1)))) /(s*exp((-a*exp((y-m)/s))-((y-m)/s))) ; else f= (1+(((1-exp(-exp((y-m)/s)))/(exp(-exp((y-m)/s))))**a))**-b ; ll=log(f); model y ~ general(ll); run;     ... View more