Code help: Monte Carlo simulation

[Harrison Kelly]

I've attached a small Do file for a Monte Carlo Simulation I am running for an economics class. For some reason the code errors. Can anyone explain what may be causing the issue?

[Clyde Schechter]

Please read the Forum FAQ for excellent advice on how to maximize your chances of getting a timely and helpful response. Among the things you will learn there:

1. Attachments are deprecated here. The preferred way to show code is by copy/pasting it into your post, between code delimiters. The use of code delimiters, if you are not already familiar with it, is explained in the FAQ.
2. Saying that the code "errors" is simply not helpful. There are an enormous number of possibilities concerning both where the code may have gone wrong and in what way it may have gone wrong. Did it cause Stata to hang? To crash? Did you get any error messages? Did it run but produce results that are incorrect? If so what are those results and what is incorrect about them? You need to give as much information as possible about what the code is actually doing, and what you want it to do in order for people to help you. The best way to do that is to actually copy/paste the response you got from Stata into your post, again, between code delimiters. Do that exactly: don't edit it in any way--there is no such thing as a "minor change."

[Harrison Kelly]

Thank you for clarifying! The stata error is
. quietly {
Working on 1 out of 1000
observation number out of range
Observation number must be between 0 and 2,147,483,619. (Observation
numbers are typed without commas.)
r(198);


The code is as follows:

clear
program drop _all
cd "###############"
capture log close
log using simulation2.log, text replace

*Endogenous x2 variable: OLS
*write a program
program define simu1
clear
set obs 5000
generate e1=rnormal()
generate x1=rnormal()
generate x2=rnormal()+e1
generate y=1+1*x1+1*x2+e1
regress y x1 x2
end
*execute the program
simu1
simulate, rep(100) seed(8964): simu1
summarize

*Endogenous x2 variable: IV
program define simu2
clear
set obs 5000
generate e1=rnormal()
generate z=rnormal()
generate x1=rnormal()
generate x2=rnormal()+e1+z
generate y=1+1*x1+1*x2+e1
eregress y x1, endogenous(x2=z x1)
end

simu2
simulate, rep(10000) seed(368): simu2
summarize

log close

[Fei Wang]

Harrison, your code intends to simulate a regression 10,000 times on a sample of 2,000 observations. Below please find a simpler code.

cap program drop mysim
program mysim, eclass
    drop _all
    set obs 2000    
    gen x = rnormal()*3 + 6
    gen e = runiform() - 0.5
    gen y = 3 + 4*x + e
    reg y x
end

simulate data_store_x=(_b[x]) data_store_cons=(_b[_cons]), reps(10000): mysim

sum data_store_x data_store_cons

ADD: The code above is a revision of the OP, not for #3.

[Hemanshu Kumar]

Harrison, the error in #3 occurs because you are trying to run a part of the code at a time, and at that point, Stata does not have the local mc in its memory. You should either run your full code at one go, or alternatively, execute it using the "Execute (include)" option available on the top-right of the toolbar in the do-file editor -- also available from the menu at View > Do-file Editor > Execute (include).