search for: xfrom

Hi, Say we have two chron vectors representing start and end date/times of an event, respectively: R> (xfrom <- chron(seq(1.25, 11, 3.25))) [1] (01/02/70 06:00:00) (01/05/70 12:00:00) (01/08/70 18:00:00) [4] (01/12/70 00:00:00) R> (xto <- chron(as.numeric(xfrom) + seq(1.5, 2.25, 0.25))) [1] (01/03/70 18:00:00) (01/07/70 06:00:00) (01/10/70 18:00:00) [4] (01/14/70 06:00:00) and we would like to...

On Thu, Aug 08, 2013 at 10:13:07AM -0700, Shuxin Yang wrote: > You should be very careful, reciprocal is very very very imprecise > transformation. Sometimes you will see big different > with and without this xform. What about constant %a, %b in this case? At least for power-of-two arguments, wouldn't it still be precise? Joerg

...rmation is conducted without "-fast-math". What I meant is if 1/Y is not exact. I measured the results before. Among all fast-math transformation, reciprocal is most annoying one because it is very imprecise. I was arguing at that time that reciprocal should be ranked as the most relax xfrom. It seems the numerical guru Steve kinda agree with me. On 8/8/13 10:32 AM, Joerg Sonnenberger wrote: > On Thu, Aug 08, 2013 at 10:13:07AM -0700, Shuxin Yang wrote: >> You should be very careful, reciprocal is very very very imprecise >> transformation. Sometimes you will see big...

Hello -- So, I have a bunch of apps on my dev box, all currently v1.0.0. I thought I could use the freezing techniques to test each app for 1.1.x compatibility individually, but that doesn''t seem to be working out... First, I checked out from http://dev.rubyonrails.org/svn/rails/tags/rel_1-1-2/ into vendor/rails Then I ran "rake rails:update". Then I went into console, and