Dear Jen,

The correct syntax for what you want to do is either

Code:

global alpha := 0.2289;
 

or

Code:

global alpha;
alpha := 0.2289;
 

Note the use of the 'assign' operator (':=') to impose a constraint on alpha.

If you use,
Code:

alpha = 0.2289;
 

then most likely alpha is made into a local variable and optimized (which you do not want), or simply ignored, if it's dependancy can't be followed from the model definition (which you also don't want).

Cheers,
Sergei