st: Variable generation

["Roy,Suryadipta" <suryadipta.roy@lawrence.edu>]

Hi,

I have data on 5 countries (a, b, c, d, e) for octy, dcty, 
dist, d1, and exp. The data are given below:

octy 	dcty	dist	d1	exp	x1	x2
a	c	5	1	50	35	50
a	d	4	0	100	35	50
b	c	3	0	50	29.167	0
b	d	8	0	100	29.167	0
c	d	2	1	50	25	50
d	c	2	1	100	50	100
e	c	1	0	50	150	0
e	d	1	0	100	150	0

I need to generate x1 and x2 for all countries based on 
the following formula:

x1 (country a)= 
1/dist(a,c)*exp(c)+1/dist(a,d)*exp(d)=1/5*50+1/4*100=35.

x2 (country a)= 
d1(a,c)*exp(c)+d1(a,d)*exp(d)=1*50+0*100=50, and so on for 
all countries.

With over 200 countries, this obviously needs some 
programming and it would be great to get some help here.

Thanks as usual for your help!
Suryadipta.
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