For variables outside loop causes exception

[David Goodger]

Gordon Williams wrote:
>     for i, obsData in enumerate(epochData):
>         Pcor[i] = obsData[3]
>         Xs[i] = obsData[4]
> 
>     Asub, Lsub= Solve_all.model_matrix(Xs[:i+1], Pcor[:i+1],Xr)
> 
> The exception is:
> 
>     Asub, Lsub= Solve_all.model_matrix(Xs[:i+1], Pcor[:i+1],Xr)
> UnboundLocalError: local variable 'i' referenced before assignment

Could epochData be empty?  If so, i and obsData will not be
declared for that call.  Local variables are not kept between
function calls.

-- David Goodger