Hi, 
I am running the following simple loop which i need some help with:
forvalues i =1/15
forvalues j=1/15{
gen mindiff`i'_`j' = mindiff``i' - mindiff`j' 
}
}
}
The problem is that not all combinations of i and j exist , so for example mindiff1_2 may not exist. Everytime the loop goes over such a variable, the loop terminates and thus stops running the loop over all consecutive variables which may exist. How do i stop the loop from terminating? 
Thank you in advance for any help. 
Akshay 
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