hg/stx-libbasic2: comparison Random.st

equal deleted inserted replaced

-:2d3e914e5ae9
+:037f3ceb4e0a
 "Created: 21.8.1997 / 18:07:00 / cg"
 "Modified: 21.8.1997 / 18:08:56 / cg"
 ! !
 !Random class methodsFor:'testing'!
+bucketTest: randy
+"A quick-and-dirty bucket test. Prints nbuckets values on the Transcript.
+Each should be 'near' the value of ntries. Any run with any value 'far' from ntries
+indicates something is very wrong. Each run generates different values.
+For a slightly better test, try values of nbuckets of 200-1000 or more;
+go get coffee.
+This is a poor test; see Knuth.
+Some 'OK' runs:
+1000 1023 998 969 997 1018 1030 1019 1054 985 1003
+1011 987 982 980 982 974 968 1044 976
+1029 1011 1025 1016 997 1019 991 954 968 999 991
+978 1035 995 988 1038 1009 988 993 976
+"
+| nbuckets buckets ntrys slot |
+nbuckets := 20.
+buckets := Array new: nbuckets.
+buckets atAllPut: 0.
+ntrys :=  1000.
+ntrys*nbuckets timesRepeat: [
+slot := (randy next * nbuckets) floor + 1.
+buckets at: slot put: (buckets at: slot) + 1 ].
+Transcript cr.
+1 to: nbuckets do: [ :nb |
+Transcript show: (buckets at: nb) printString, ' ' ]
+"Execute this:
+Random bucketTest: Random new
+"
+!
 chiSquareTest
 " Chi-Squared Test - from R.Sedgewick's 1st ed. of 'Algorithms',
 o N = number of samples
 o r  = range of random numners is [0,r)      -- condition: N >= 10r.
 nextInteger
 "return the next integral random number,
 in the range 0 .. 16r3FFFFFFF.
 From Sedgewick's 'Algorithms', based on Lehmer's method"
-"the times: is a kludge - times does not convert to LargeInteger on overflow"
 self step.
 ^ seed
 "|r|
 r := Random new.
 ! !
 !Random class methodsFor:'documentation'!
 version
-^ '$Header: /cvs/stx/stx/libbasic2/Random.st,v 1.21 1998-08-21 12:47:38 cg Exp $'
+^ '$Header: /cvs/stx/stx/libbasic2/Random.st,v 1.22 1999-08-12 09:42:31 cg Exp $'
 ! !

changeset 793	037f3ceb4e0a
parent 680	a7b98fdac3dc
child 840	5f6559515588