I think you want:
. clear
. set obs 81
. range x -2 2
. expand 81
The "imprecision" you are seeing is a side-effect of storing decimal
numbers in binary. There is a FAQ somewhere on that.
--Nick W
-----------------------------------------------------------
Nicholas Winter, Ph.D. P 202.939.5343
Policy Studies Associates F 202.939.5732
1718 Connecticut Avenue, NW [email protected]
Washington, DC 20009-1148 www.policystudies.com
-----------------------------------------------------------
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: Friday, June 14, 2002 11:32 AM
> To: [email protected]
> Subject: st: St: Dataset generation
>
>
> Please could somebody explain to me how this could occur:
>
> I want to generate a dataset with 6561 observations, with two
> variables, let us say x and y, which take values between -2 and 2,
> with step value 0.05. The aim of this is to test a function which I
> have programmed which is causing some trouble. Therefore I need 81
> occurences of x==-2, and 81 of x==-1.95 and so on for both x and y.
> If I construct x as follows (crude so feel free to suggest
> alternatives)
>
> egen ind=fill (1 2)
> replace ind=ind-1
> gen x=int(ind/81)
> replace x=(x/20)-2
>
> this should work, and does when the data is displayed to 2 decimal
> places. However closer examination of the data with the data browser
> shows some anomalies, where rather that x==-.95 it actually reads
> x==.-9499999. This occurs for many values in between -1 and 1 and
> attempts to rectify it using
>
> gen x2=round(x,0.05)
>
> have not bourne fruit. What am I missing?
>
> Many thanks in advance,
> Julian
> ________________________________________________________________
>
> DISCLAIMER:
>
> This e-mail and any files transmitted with it are confidential
> and intended solely for the use of the individual or entity to
> whom it is addressed. If you are not the intended recipient
> you are prohibited from using any of the information contained
> in this e-mail. In such a case, please destroy all copies in
> your possession and notify the sender by reply e-mail. Heriot
> Watt University does not accept liability or responsibility
> for changes made to this e-mail after it was sent, or for
> viruses transmitted through this e-mail. Opinions, comments,
> conclusions and other information in this e-mail that do not
> relate to the official business of Heriot Watt University are
> not endorsed by it.
> ________________________________________________________________
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
