@acer Thank you so much, just perfect.

@Bart Thank you for your message. Unfortunately, the graph cannot be plotted. The error message is "Error, (in plots:-display) unexpected option: stylesheet = [edgethickness = .1]". Maybe you have a solution to this error. Thank you in advance.

@Carl Love You're right. Thanks a lot. 

Best

@Carl Love Perfect, as always. Thank you so much.

@Carl Love Very useful, as always

@Markiyan Hirnyk I really appreciate your help. Yet the mistake in my example does not deserve the term "dirtily formulated". It's a bit unfair, don't you think? 

@Carl Love Thank you. I think that now I have everything I need. As you noticed, my goal is just to draw samples.

Regards,

@Markiyan Hirnyk Sorry, the example was false, not the formulation. I should have written:

"For example, with i=20 and x=5, the random variable is an integer between 15 and 25 except 20"

By the way, I did not think it could be so easy to build the customized discret variable I was looking for.

Best

@Kitonum Thank you, very useful! Just for the record, the possible numbers do not include i: 

i-x, i-x+1, i-x+2 ... i-1, i+1, i+2... i+x

So, there are 2x possible numbers for each i, and a probability of 1/2x for each number.

Best

@Markiyan Hirnyk Thanks! 

@John Fredsted @Carl Love

Very useful comments and suggestions. Thanks a lot.

Best,

@John Fredsted THANKS!

@Joe Riel 

It seemed that the current directory was not the problem. I found a solution, which is as follows:

for y from 1 to 5000 do 

save SIM, sprintf("SIM_%d.mpl", y) ;

FileTools[Text][Open](sprintf("SIM_%d.mpl", y), append = true) ;

FileTools[Text][WriteString](sprintf("SIM_%d.mpl", y), sprintf("Threads:-Map(SIM, 5000, %d)", y)) ;

od

I truly appreciated your help. Thanks a lot.

@Joe Riel 

Thanks a lot for your time! I am sorry but it does not work. The error message says "Error, (in fprintf) permission denied". Any suggestion? 

Thanks again.

@Joe Riel Thanks for the advice!