program define nlsm_h /* varname newvar */
	version 3.0
	local v "`1'"
	local g "`2'"
	tempvar res 
	local type : type `1'
	quietly { 
		gen `type' `res' = `v'
		replace `res'=(`v'[_n-1]+2*`v'+`v'[_n+1])/4 in 2/-2
	}
	rename `res' `g'
end