simpson@aplcen.apl.jhu.edu (Simpson David Grant) (03/09/91)
Can someone explain what is happening when I try to calculate
factorials in the following J session? I do this right after
starting up J (version 3):
!9
362880
!174
1.7=e309
!9
1
All following attempts to calculate factorials also produce 1.
What gives?
David Simpsonsam@kalessin.jpl.nasa.gov (Sam Sirlin) (03/12/91)
In article <1991Mar9.040541.28914@aplcen.apl.jhu.edu>, simpson@aplcen.apl.jhu.edu (Simpson David Grant) writes: |> In article <1991Mar9.040541.28914@aplcen.apl.jhu.edu>, simpson@aplcen.apl.jhu.edu (Simpson David Grant) writes: |> |> Can someone explain what is happening when I try to calculate |> factorials in the following J session? I do this right after |> starting up J (version 3): |> |> !9 |> 362880 |> !174 |> 1.7=e309 |> !9 |> 1 |> |> All following attempts to calculate factorials also produce 1. |> What gives? |> |> David Simpson What version/machine? With 2.9 on my SPARC 1 I get: !9 362880 !174 _ !9 362880 !4 24 which looks fine. Version 2.4 on my PCAT bombs when it trys !174 (overflow). Sounds like infinity doesn't quite work in your version. -- Sam Sirlin Jet Propulsion Laboratory sam@kalessin.jpl.nasa.gov
simpson@aplcen.apl.jhu.edu (Simpson David Grant) (03/13/91)
>|> In article <1991Mar9.040541.28914@aplcen.apl.jhu.edu>, simpson@aplcen.apl.jhu.edu (Simpson David Grant) writes: >|> >|> Can someone explain what is happening when I try to calculate >|> factorials in the following J session? I do this right after >|> starting up J (version 3): >|> >|> !9 >|> 362880 >|> !174 >|> 1.7=e309 >|> !9 >|> 1 >|> All following attempts to calculate factorials also produce 1. >|> What gives? >|> I got these results with J version 3 for the PC, running on my Zeos 386. I tried this same software today on an IBM AT (80286) with different results -- it hangs the computer for !174, but does not answer "1" for every factorial like my 386 does. David Simpson
sam@kalessin.jpl.nasa.gov (Sam Sirlin) (03/14/91)
In article <1991Mar13.042856.23984@aplcen.apl.jhu.edu>, simpson@aplcen.apl.jhu.edu (Simpson David Grant) writes: |> I got these results with J version 3 for the PC, running on my |> Zeos 386. I tried this same software today on an IBM AT (80286) |> with different results -- it hangs the computer for !174, but |> does not answer "1" for every factorial like my 386 does. |> I tried this in version 2.9 on IBM PCAT and Everex 386. The pc version of 2.9 doesn't have infinity, and both machines give domain errors for factorial arguments > 170, but work fine afterwards. Maybe you should grab 2.9 from watserv. The sun4 version of 2.9 seems to have a limited implementation of infinity. -- Sam Sirlin Jet Propulsion Laboratory sam@kalessin.jpl.nasa.gov
hui@yrloc.ipsa.reuter.COM (Roger Hui) (03/19/91)
_ (infinity) is not yet available, and this is indicated as such in the status.doc file. It is not yet available because (a) the implications of _ are pervasive and (b) there is uneven hardware and C compiler support for _. Nevertheless, !174 should have failed more gracefully than it did. If you'd tell me the machine and the J version, it would help me a great deal in tracking down this error. (J runs on over a dozen different machines. On a given error, the possibilities are numerous: it happens on all versions; it happens on only some machines; it is my error; it is a C compiler bug; etc. etc. etc.) Roger Hui Iverson Software Inc., 33 Major Street, Toronto, Ontario M5S 2K9 (416) 925 6096