There isn't a limit per se, but if you add too many variables, you'll eventually hit a maximum number of elements in a matrix for EViews to handle. This will be a function of workfile size, number of equations and number of variables. But, for example, I can create a SUR with 200 equations without hitting that limit fairly easily:
Code: Select all
create u 1000
!n =200
system s
coef(!n ) alpha
coef(!n ) beta
for !i=1 to !n
series y!i=nrnd
series x!i=nrnd
s.append y!i=alpha(!i) + beta(!i)*x!i
next
s.sur
Your singularity problem is more likely to be caused by a true singularity.