Re: why no result & no error from this recursion

*To*: mathgroup at smc.vnet.net*Subject*: [mg82436] Re: [mg82403] why no result & no error from this recursion*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Sat, 20 Oct 2007 05:51:46 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200710190904.FAA05304@smc.vnet.net> <DB2B10DE-2D39-482A-ACA4-6DDB5CECB1E4@jeol.com>*Reply-to*: murray at math.umass.edu

When the evaluation ended (very quickly, and with no result), the front end was immediately ready for the next input I typed. Sseziwa Mukasa wrote: > > On Oct 19, 2007, at 5:04 AM, Murray Eisenberg wrote: > >> Why does the following recursion produce neither a result nor an error >> message -- nor a system crash? >> >> Block[{$RecursionLimit=50002}, (If[#<1, "", "." <> #0[# - 1]] &)[50000]] >> >> I even tried setting $RecursionLimit=Infinity, but no change. >> >> I presume this is just bumping up against a hardware/OS limit, so I'm >> surprised to get no error message and no crash. > > My guess is that the front end is having problems formatting 50000 '.' > for display. I've noticed sometimes that calculations that generate > long strings on output can appear to have hung but the kernel has not > crashed and the front end is unresponsive. > > Regards, > > Ssezi > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**why no result & no error from this recursion***From:*Murray Eisenberg <murray@math.umass.edu>