Creating longitudinal dataset

[ChuksManuel]

Hello programmers,

I am trying to implement this piece of code from a SAS guide. I can't implement it as it's giving me error messages.

Can anyone explain why it doesn't work?

 l=t(root(eps));      /* calculate cholesky root of cov matrix eps */  
 z=normal(j(1,n,seed));  /* generate n samplesize normals */    
xx=l*z*v;               /* multiply by cholesky root and variance */  
tx=t(xx);    
do i=1 to &n ; 
   Group[i] = round(ranuni(int(time()))); 
   x[i] = rannor(int(time()))*2 ;  
   do r=1 to &mm ;    
       b0[r]=-.2-2.6*cos((r-&m)*3.14159/ 30)* / );    
       yy[i,r]=b0[r]*Group[i]+3.5*sin(2*3.14159*x[i]/5);
     end;    
 end;   
 yy=yy+tx;               /*yy with multivariate normal error*/

Thanks

[RichardDeVen]

And what are the errors ?

[ChuksManuel]

[Kurt_Bremser]

The comment mentions a matrix. Are you sure this is data step code, and not rather part of a proc iml?

Otherwise, it may be you are missing a custom function definition.

[Ksharp]

It is IML code , not Data step .

You need SAS/IML module . Calling @Rick_SAS 

[Rick_SAS · Accepted solution]

Start by using 

PROC IML;

as the first line of the program. Then you need to define the covariance matrix, eps. You can either read it from a SAS data set into a matrix or you can input it manually:

proc iml;
eps = {
9 3   1,
3 4   1.3,
1 1.3 2};
 
...

[ChuksManuel]

Thanks Dr Rick!