I had a possibly analogous problem writing something in R which does not have comparison tolerance. So, instead of a simple comparison like this
maxSect<- seclim <= sectorSums; I had to do something like this maxSect<- 1e-08<seclim-sectorSums; # R lacks tolerance However, I've been unable to uncover something like your problem in J after running several million tests based on different guesses about how the two vectors might be related. On Thu, Jul 2, 2015 at 11:34 AM, John Baker <[email protected]> wrote: > This has been a rare intermittent error. I am beginning to suspect > something of a a non J'ey nature is going on. If I can ever collect a > datastream that forces the issue I will have it bronzed. > > On Wed, Jul 1, 2015 at 9:04 PM, Devon McCormick <[email protected]> > wrote: > > > I ran a test for a few million lookups using i. on floating point numbers > > and found no discrepancy but I created "sl" by a random selection from > > "fl", so this may not properly replicate your issue. > > > > This was in the new J v. 8.04. > > > > On Wed, Jul 1, 2015 at 3:59 PM, <[email protected]> wrote: > > > > > Can you give an example, exactly? > > > > > > I think this would fail only if some sl is not found in fl. > > > > > > Henry Rich > > > > > > ---- John Baker <[email protected]> wrote: > > > > I have observed that this sometimes fails > > > > > > > > fl=. 78.9999 ..... some floating list > > > > sl=. 78.9999 .... some subset of (fl) > > > > > > > > (666.666 #~ #sl) (fl i. sl) } fl NB. searching floats > > > > > > > > where this always works > > > > > > > > (666.666 #~ #sl) ((<.fl) i. <. sl) } <. fl NB. searching integers > > > > > > > > When I came across this I thought this could be fixed by comparison > > > > tolerance. > > > > > > > > (666.666 #~ #sl) (fl (i. !.0) sl) } fl > > > > > > > > but no luck. > > > > > > > > Either this is a bug in J or I am not properly setting comparison > > > tolerance > > > > to 0. > > > > > > > > > > > > Floating point - one of life's more intractable necessary evils. > > > > > > > > -- > > > > John D. Baker > > > > [email protected] > > > > > ---------------------------------------------------------------------- > > > > For information about J forums see > http://www.jsoftware.com/forums.htm > > > > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > > > > > > -- > > Devon McCormick, CFA > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > -- > John D. Baker > [email protected] > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Devon McCormick, CFA ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
