# st: complicated nonlinear least sqaures problem

 From Amit Khandelwal To statalist@hsphsun2.harvard.edu Subject st: complicated nonlinear least sqaures problem Date Thu, 5 Aug 2004 13:05:24 -0400

Hello,

I am new to the Stata programming world (I want to switch from
Matlab). I want to program the following equation (in TeX notation)

ln q_{ijt} = (1-s)*ln(b_{i}) - ln P_{jt} - s*ln(prices) + ln(gdp) + error

where P_{jt}=\sum_{i}[b_{i}p_{it}]^{1-s}

My data is q, prices and gdp. t is a time subscript, i is a sender and
j is a receiver. So, q_{ijt} is the amount sent by i to j at time t.
Since each reciever j receives from many i's, I need some way to sum
over the i's. I am clueless as to how to code this. I was able to
follow the examples in the nl help, but have no idea how to extend to
this problem. Any ideas would be greatly appreciated.

Thanks!
Amit
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