GLM + restrictions on coefficients

[Sunny_Sun]

Hi,

I am having a hard time to run proc glm. Here is what I want to do:

proc glm data=a;

     model y=x1 x2 x3 x4;

run;

where I need to restrict x1=x2.

How can I do it in proc glm?

Thanks in advance.

Thanks,

Sunny

[Doc_Duke · Accepted solution]

proc glm data=a (WHERE=(x1=x2));

     model y=x1 x3 x4;

run;

This will run the GLM on just those cases where x1=x2.  I removed x2 from the model because it makes the design matrix singular.

[Sunny_Sun]

Many thanks!