The floor of infinity being infinity is not the real problem, opinion. Or at least not the only problem. And, integer infinity is not a particularly new concept: https://simple.wikipedia.org/wiki/Aleph_null
Infinity is defined as larger than any number, and larger is not equal. Or, these sorts of "numeric quality" things can defy logic because they are not specific values. But infinity is not the only example of a problem with that expression. Consider this: (= <.) 0.5+2^128 1 Basically, floating point notation is not capable of representing large fractional values. Meanwhile, you could claim that J's implementation of infinity is an integer infinity (since all values greater than a limit in floating point notation are integer values). Anyways, with that out of the way -- what is it that you're trying to do? And, why is infinity a problem there? And, is this an issue for you? datatype <.2^10 integer datatype <.2^100 floating Thanks, -- Raul On Sun, Aug 2, 2020 at 2:45 AM Skip Cave <[email protected]> wrote: > > I use the (=<.) verb to find integers in a list: > > > * (=<.)1 2.5 2.7 3 4.5 6* > > *1 0 0 1 0 1* > > * (#~(=<.))1 2.5 2.7 3 4.5 6* > > *1 3 6* > > I ran across an interesting result when infinity is in the list: > > * (=<.)1 2.5 __ 3 4.5 6* > > *1 0 1 1 0 1* > > * (#~(=<.))1 2.5 __ 3 4.5 6* > > *1 __ 3 6* > > > So J is saying that the floor of infinity is infinity (and the ceiling of > infinity is also infinity). Since infinity is not a number, it would seem > that an error should be generated when taking the floor of infinity, or > perhaps NAN, or a zero? In any case, this messes up my nice integer-finding > verb. Is the\re a mathematical justification for defining the floor of > infinity to be infinity? > https://math.stackexchange.com/questions/981708/limit-of-floor-function-when-x-goes-infinity > > > Skip > > > Skip Cave > Cave Consulting LLC > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
