rfc1439.txt

<VC++网络游戏建摸与实现>源代码

   #!/usr/local/bin/perl

   for $bits (6..31) {
           &Compute($bits);
           }
   exit(0);

   # ------------------------------------------------------------

   sub Compute {
           $bits = $_[0];
           $num = 1 << $bits;
           $cnt = $num;

           print "bits $bitsnumber $num:0;

           for ($prob = 1; $prob > 0.99; ) {
                   $prob *= $cnt / $num;
                   $cnt--;
                   }

           print "", $num - $cnt, "$prob0;

           for (; $prob > 0.98; ) {



Finseth                                                         [Page 6]

RFC 1439            Uniqueness of Unique Identifiers          March 1993


                   $prob *= $cnt / $num;
                   $cnt--;
                   }
           print "", $num - $cnt, "$prob0;

           for (; $prob > 0.95; ) {
                   $prob *= $cnt / $num;
                   $cnt--;
                   }
           print "", $num - $cnt, "$prob0;

           for (; $prob > 0.90; ) {
                   $prob *= $cnt / $num;
                   $cnt--;
                   }
           print "", $num - $cnt, "$prob0;

           for (; $prob > 0.80; ) {
                   $prob *= $cnt / $num;
                   $cnt--;
                   }
           print "", $num - $cnt, "$prob0;

           print "0;
           }

Appendix: Perl Program Output

   bits 6  number 64:
           2       0.984375
           3       0.95361328125
           4       0.90891265869140625
           5       0.85210561752319335938
           6       0.78553486615419387817

   bits 7  number 128:
           3       0.9766845703125
           3       0.9766845703125
           5       0.92398747801780700684
           6       0.88789421715773642063
           8       0.79999355674331695809

   bits 8  number 256:
           3       0.988311767578125
           4       0.97672998905181884766
           6       0.94268989971169503406
           8       0.89542306910786462204
           12      0.76969425214152431547



Finseth                                                         [Page 7]

RFC 1439            Uniqueness of Unique Identifiers          March 1993


   bits 9  number 512:
           4       0.98832316696643829346
           6       0.97102570187075798458
           8       0.94652632751096643648
           11      0.89748056780293572476
           16      0.78916761796439427457

   bits 10 number 1024:
           6       0.98543241551841020964
           7       0.97965839745873206645
           11      0.94753115178840541244
           16      0.88888866335604777014
           22      0.79677613655632184564

   bits 11 number 2048:
           7       0.98978773152834598203
           10      0.97823367137821537476
           15      0.94990722378677450166
           22      0.89298119682681720288
           31      0.79597589885472519455

   bits 12 number 4096:
           10      0.98906539062491305447
           14      0.97800426773009718762
           21      0.94994111694430838355
           30      0.89901365764115603874
           44      0.79312138620093930452

   bits 13 number 8192:
           14      0.98894703242829806733
           19      0.97932692503837115439
           30      0.94822407309193512681
           43      0.89545741661906652631
           61      0.7993625840767998314

   bits 14 number 16384:
           19      0.98961337517641645434
           27      0.97879319536756481668
           42      0.94876352395820107155
           60      0.89748107890372830209
           86      0.79973683158771624591

   bits 15 number 32768:
           27      0.98934263776790121181
           37      0.97987304880641035165
           59      0.94909471808051404373
           84      0.89899774209805793923
           122     0.79809378598190949816



Finseth                                                         [Page 8]

RFC 1439            Uniqueness of Unique Identifiers          March 1993


   bits 16 number 65536:
           37      0.98988724065590050216
           52      0.97996496661944154649
           83      0.94937874420413270737
           118     0.89996948010355670711
           172     0.79884228150816105618

   bits 17 number 131072:
           52      0.98993311138884398925
           74      0.97960010416289267088
           117     0.94952974978505377823
           167     0.89960828942716541956
           243     0.79894309171178368167

   bits 18 number 262144:
           74      0.98974844864797828503
           104     0.97977315557223210174
           165     0.94968621078621640041
           236     0.8995926348279144058
           343     0.7994422793765953994

   bits 19 number 524288:
           104     0.98983557888923057178
           147     0.97973841652874515962
           233     0.94974719445364064185
           333     0.89991342619657743729
           485     0.79936749144148444568

   bits 20 number 1048576:
           146     0.98995567500195758015
           207     0.97987072919607220989
           329     0.94983990872655321702
           471     0.89980857451706741656
           685     0.79974215234216872172

   bits 21 number 2097152:
           206     0.98998177463778547214
           292     0.97994400939715686771
           465     0.94985589918092261374
           666     0.89978055267663470396
           968     0.79994886751736571373

   bits 22 number 4194304:
           291     0.98999013137747737812
           413     0.97991951242142538714
           657     0.94991674892578203959
           941     0.89991652739633254399
           1369    0.79989205747440361716



Finseth                                                         [Page 9]

RFC 1439            Uniqueness of Unique Identifiers          March 1993


   bits 23 number 8388608:
           412     0.98995762604049764022
           583     0.97997846530691334888
           929     0.94991024716640248826
           1330    0.89999961063320443877
           1936    0.79987028265451087794

   bits 24 number 16777216:
           582     0.98997307486745211857
           824     0.97999203469417239809
           1313    0.94995516684099989835
           1881    0.89997049960675035152
           2737    0.79996700222056416063

   bits 25 number 33554432:
           822     0.98999408609360783906
           1165    0.9799956928177964155
           1856    0.9499899669674316538
           2660    0.8999664414095410736
           3871    0.79992328289672998132

   bits 26 number 67108864:
           1162    0.98999884535478044345
           1648    0.9799801637652703068
           2625    0.94997437525354821997
           3761    0.89999748465616635773
           5474    0.79993922903192515861

   bits 27 number 134217728:
           1644    0.9899880636014986024
           2330    0.97998730103356856969
           3712    0.94997727934463771504
           5319    0.89998552434244594167
           7740    0.79999591580103557309

   bits 28 number 268435456:
           2324    0.98999458855588851058
           3294    0.97999828329325222587
           5249    0.94998397932368705554
           7522    0.89998576049206902017
           10946   0.79999058777500076101

   bits 29 number 536870912:
           3286    0.98999717306002099626
           4659    0.97999160965267329004
           7422    0.94999720388831232487
           10637   0.89999506567702891591
           15480   0.7999860979665908145



Finseth                                                        [Page 10]

RFC 1439            Uniqueness of Unique Identifiers          March 1993


   bits 30 number 1073741824:
           4647    0.98999674474047760775
           6588    0.97999531736215383937
           10496   0.94999806770951356061
           15043   0.89999250738244507275
           21891   0.79999995570982085358

   bits 31 number 2147483648:
           6571    0.98999869761078929109
           9316    0.97999801528523688976
           14844   0.94999403283519279206
           21273   0.89999983631135749285
           30959   0.79999272222201334159

References

   Bruce Lansky (1984).  The Best Baby Name Book.  Deephaven, MN:
   Meadowbrook.  ISBN 0-671-54463-2.

   Lareina Rule (1988).  Name Your Baby.  Bantam.  ISBN 0-553-27145-8.

Security Considerations

   Security issues are not discussed in this memo.

Author's  Address

   Craig A. Finseth
   Networking Services
   Computer and Information Services
   University of Minnesota
   130 Lind Hall
   207 Church St. SE
   Minneapolis, MN 55455-0134

   EMail: [e-mail] or
          [e-mail]

   Phone: [phone]
   Fax: [phone]











Finseth                                                        [Page 11]