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From |
annoporci <annoporci@gmail.com> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
st: rounding the minimum of a negative number |

Date |
Thu, 10 Jan 2013 03:59:29 +0800 |

Dear Statalist, This is a problem for which I have found a solution. I am sending this to Statalist for the record and/or further discussions if warranted. I have data whose minimum is something like -1.9810 which I want to "transform" into -1.9900. By "transform" I mean that I want to "floor" it to the nearest smaller rational number with 2 non-zero decimal digits. The -round(x,y)- function takes 2 arguments that allow you to select the precision of the rounding. But the rounding is to the nearest greater rational number. The -floor- function takes only 1 argument and "floors" to a natural number without decimal digits. Or that is what I gather from Stata help. Perhaps there is some undocumented extension to floor or some more general function by another name? Thus, using -round- on -1.9810 yields -1.98. There does not seem to be an option to make -round- act like -floor-. Here is my workaround to this shortcoming (rather obvious, I know): scalar m = floor(100*r(min))/100 Is that the state of the art? I must admit that along the way, I observed some unexpected behaviour, namely: set obs 10 gen x = -1.98100 sum(x), meanonly scalar min1 = "`r(min)'" scalar min2 = r(min) scalar list min2 = -1.9809999 min1 = -1.980999946594238 I did not expect -1.98100 to "become" (or appear so): -1.980999 or -1.980999946594238. It looks like something to do with the idea that -1.98100 and -1.98109 are treated as the same number at the level of precision Stata assumes I'm interested in. -- Patrick Toche. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: rounding the minimum of a negative number***From:*Nick Cox <njcoxstata@gmail.com>

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