All,
Wow! Chris Burke's suggestion about rounddist works better than what I
expected.
g=.1 rounddist "1 (* 172 % +/"1)"1 ] f01
+/172=+/"1 g
100000 NB. Now ALL the 6-digit vectors generated sum to 172!!
NB. To check:
>./,g
145
<./,g
0
NB. However, some of the vectors contain integers > 70, and/or some include
a zero, which is out-of-spec:
NB. Find & count 6 integer vectors in g that have integers > 70 in them
#g#~+./"1]100000 6 $70<,g
5006
NB. So there are still about 5% of the 6 integer vectors that miss the
original spec of integers 1-70
#g#~+./"1]100000 6 $0=,g
4250
And another 4.2% that contain zeros
Skip
Skip Cave
Cave Consulting LLC
On Wed, Jun 27, 2018 at 6:09 PM chris burke <cbu...@jsoftware.com> wrote:
> Perhaps use the distributed rounding function from the numeric script? For
> example:
>
> load 'numeric'
>
> (+/,]) 1 rounddist a * 172 % +/a=. 42 23 5 20 41 40
> 172 42 23 5 21 41 40
>
> (+/,]) 1 rounddist a * 172 % +/a=. 50 35 50 8 19 11
> 172 50 35 49 8 19 11
>
>
> On Wed, Jun 27, 2018 at 3:47 PM, Skip Cave <s...@caveconsulting.com>
> wrote:
>
> > Devon,
> >
> > That 0-1 fraction method is a really nice way to generate lots of sets
> of 6
> > random integers 1-70 that sum to 172.
> > That got me to thinking -- shouldn't we be able to make all the generated
> > 6-integer sets sum to 172?
> >
> > f01=. 1e5 6?@$0 NB. Generating the fractions
> >
> > NB. Now if we instument your verb a bit more:
> >
> > itt1=. f01#~c=.172=+/"1 b=.([: <. 0.5 + ] * 172 % +/"1)"1 ] f01
> >
> > $itt1
> >
> > 55085 6
> >
> > NB. Not bad. Over half of the strings sum to 172.
> >
> >
> > NB. What about the other half (invert the c selection vector)?
> >
> > 5{.b#~-.c
> >
> > 42 23 5 20 41 40
> >
> > 50 35 50 8 19 11
> >
> > 37 34 34 17 22 27
> >
> > 49 10 25 2 34 53
> >
> > 30 14 44 15 32 38
> >
> >
> > How far off are the rest of these strings ?
> >
> > d=.172-+/"1 b#~-.-.c
> >
> > 20{.d
> >
> > 1 _1 1 _1 _1 _1 1 1 _1 1 1 _1 1 1 1 1 1 1 _1 1
> >
> > _20{.d
> >
> > 1 1 _1 _1 1 1 _1 _1 _1 _1 _1 1 _1 2 _2 1 1 _1 _1 1
> >
> >
> > >./d
> >
> > 2
> >
> > <./d
> >
> > _2
> >
> > NB. Looks like the rest of the strings are off by as much as +/- 2
> >
> >
> > So we should be able find the discrepancy in the remaining strings, and
> > randomly pick one or more of the integers in each of the strings to add
> or
> > subtract 1 or 2 to. Then all the strings will sum to 172.
> >
> >
> > I'll leave that exercise to the reader...
> >
> >
> > Skip
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
