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st: RE: Precission problems with -cumul-

From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   st: RE: Precission problems with -cumul-
Date   Wed, 26 Jan 2005 13:53:36 -0000

I don't know, but I can make a guess, knowing that if I am 
wrong someone can improve on my guess. (According to Karl Popper, 
this is the essence of scientific method.) 

I guess this is purely historic. The intent of -cumul-, introduced
in Stata 3.0, was always, at least primarily, as a preprocessor to 
allow plots of the cdf. For graphical purposes, -float- is surely 

I guess also that it has taken this long -- from 1992 to 2005 -- 
for someone to say that in fact precision does matter to them
here. (Perhaps others found the same thing, but just did the 
calculations themselves from first principles.) 

I guess also that StataCorp will oblige you and make the tweak in an 
ado update sooner or later. 

[email protected] 

Jann, Ben
> the -cumul- command (which computes the empirical 
> cumulative distribution function) enforces float 
> storage type for the generated variable (that is,
> the storage type of the generated variable will 
> always be float no matter what the default storage 
> type is). This gives rise to precission problems 
> in some applications.
> Can someone explain me the rationale behind 
> enforcing float storage type in this context?

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