clear
set obs 1600
set seed 14171
set more off
set type double


*****************
* create data for Problem 3
*****************

gen x = invnorm(uniform())
gen id = floor((_n - 1) / 8)
bys id: gen fe = invnormal(uniform())
bys id: replace fe = fe[1]
gen y = ( (exp(1.4*x + fe) / (1 + exp(1.4*x + fe))) > uniform() )

*****************



**
** run built-in clogit comand for comparison
**
logit y x
clogit y x, group(id)


program drop _all
program myclogit

 args todo b lnf
 tempvar xb
 mleval `xb' = `b', eq(1)

 **
 ** YOUR CODE GOES HERE **
 **

end


**
** Drop the panels with all 1's and the panels with all 0's
**
bys id: gen myN = _N
bys id: egen sum_y = sum(y)
drop if myN == sum_y | sum_y == 0

ml model d0 myclogit (y = x, noconstant)
ml maximize