Thanks. This is weird. The C and Fortran versions seem to agree.
Marco On Thu, Nov 9, 2023 at 9:49 PM Frank Gönninger | Gönninger B&T < frank.goennin...@goenninger.net> wrote: > Hi Marco, > > > > on AllegroCL 11.0 beta Enterprise Edition I get diverging results starting > at j = 21… > > > > Lisp: j = 21; ss = 0.00028959847986698150 > > C: j = 21; ss = 0.00028959847986698151 > > > > FWIW … > > > > Best, > > Frank > > > > *Von: *<owner-lisp-...@lispworks.com> im Auftrag von "Marco Antoniotti > (as marco dot antoniotti at unimib dot it)" <lisp-...@lispworks.com> > *Antworten an: *Marco Antoniotti <marco.antonio...@unimib.it> > *Datum: *Donnerstag, 9. November 2023 um 21:23 > *An: *LispWorks <lisp-...@lispworks.com>, Discussion list for Common Lisp > professionals <pro@common-lisp.net> > *Betreff: *Help with bit bashing code: differences between C and CL > > > > Dear all, > > > > I am hitting a wall with the attached code in CL and C versions. For > those interested, this is code lifted from Knuth's pages on random number > generation (https://www-cs-faculty.stanford.edu/~knuth/programs.html#rng). > > The problem is that there is a discrepancy in the "problem" loop between > the CL and the C and I cannot figure out why, although the culprit may be > that CL does not have "proper" 64 bits ints. > > I am running on LW 8.x on an Intel Mac. I have not tried on other CL > implementations/platforms. I compile the C code with clang (Apple clang > version 15.0.0 (clang-1500.0.40.1) > > > > If you run the code, you will see that the discrepancy appears at 'j = 14' > in the loop. > > > > What gives? > > Thanks > > Marco > > > > > > > -- > > Marco Antoniotti, Professor tel. +39 - 02 64 48 79 01 > DISCo, Università Milano Bicocca U14 2043 http://dcb.disco.unimib.it > Viale Sarca 336 > I-20126 Milan (MI) ITALY >
