On Thu, Aug 5, 2010 at 2:59 PM, Dr. David Kirkby <david.kir...@onetel.net> wrote: > On 08/ 5/10 06:17 PM, Sergey Bochkanov wrote: >> >> Hello, >> >>> Hmmm... Didn't thought about this situation yet. Definitely we can't >>> solve this problem with any kind of regular expressions. One >>> possible solution is to round data before printing. So both >>> 1.00000000000001 and 0.99999999999999 will become 1.000000. >> >> ...however, we still can have problems when rounding X=0.000499999 up >> to three digits. With original X we will have 0.000. But with >> perturbation as small as 0.000000002 we will round to 0.001. > > I've never done this, but the most logical thing to me seems to be to look > at the absolute magnitude of the relative error, for all cases except when > the expected value is 0. But I guess on cases where the numbers are not > close to 1, or other special cases one could think up, the current system is > probably the simplest.
That would be nice. But it's a bit tricky to write, since the doctest check happens solely on the basis of string comparison; to do something clever like looking at relative error would require some sort of marking in the expected output to turn on the relative-error check, and some sort of parser to find the numbers in the expected/found outputs, and possibly some sort of marking on a per-number basis in the expected output to say what relative error is allowed on that number. (If the expected output is 1.23456*x^10000, with a relative error allowed of 1e-3, you probably don't want to allow 1.23456*x^10001 !) I would be in favor of something like this, if we could decide on a set of markings in the expected output that didn't interfere too much with the documentation aspect; but nobody has written it yet. The three-dots notation is much, much stupider than this... it is just a wildcard that will match an arbitrary string of characters (the equivalent of .* as a regex, or * as shell globbing). And we didn't even write it; it's a standard part of the Python doctest system. Carl -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
