Make sure that the sum is 172.
(,~172-+/)>:?5#70 15 9 64 21 20 43
Discard results where the first item is not between 1 and 70
(,~172-+/)>:?5#70
_31 67 61 41 12 22
This must be faster than discarding sets where the sum is not 172.
Thanks,
Bo.
Den 19:29 tirsdag den 26. juni 2018 skrev Louis de Forcrand
<ol...@bluewin.ch>:
Hi,
If I understand your wording, you would like to generate n “multisets” of 6
random numbers which sum to 172. I say multiset because I imagine that order
doesn’t matter, but that multiplicity does (so numbers can be repeated).
If speed is a concern, then you could generate all possible multisets and then
select some at random. This takes some memory though, but I can run it on my
phone so it shouldn’t be too bad. What follows was thrown together quickly, and
could probably be improved.
g=: 4 : 0
'm M'=. x
'n s'=. y
if. n<:0 do. i.1 0 return. end.
min=. m >. s - M * d=. <:n
max=. M <. s <.@% n
p=. min ivl max
; (,"_ 1 ,&M g d , s&-)&.> p
)
ivl=: [ + 0 i.@>. >:@-~
$t=: 1 70 g 6 172 NB. 1141667*6 integers!
sel=: t {~ ?@$&(#t)
(m,M) g n,s generates all increasing sequences of n integers which sum to s,
all between m and M inclusive (provided I didn’t make any mistakes!).
If what you want is actual sets, then g can be modified slightly to yield
strictly increasing sequences, and the space required will be slightly lessened.
Cheers,
Louis
> On 26 Jun 2018, at 16:12, Skip Cave <s...@caveconsulting.com> wrote:
>
> I want to generate n sets of 6 random integers from 1->70 where each set of
> 6 integers sums to 172
>
> Here's my first try:
>
> ts =: 3 : 0
>
> b=: 2 6$0
>
> for. i.y do. a=:1+6?70
>
> b=:b,a
>
> end.
>
> b#~172=+/"1 b
>
> )
>
> Test it:
>
> ts 1000
>
> 27 60 5 24 53 3
>
> 38 35 3 15 57 24
>
> 16 29 19 50 4 54
>
> This generates some 6-element vectors that sum to 172 by elimination, but I
> don't have control of how many vectors it produces.
>
>
> I want to change the logic in the loop so that it keeps generating sets of
> 6 random integers, testing whether they sum to 172, saving just the sets
> that sum to 172, until I have saved y random sets that sum to 172, and then
> exits.
>
>
> Any help would be appreciated.
>
>
> Skip
>
>
> Skip Cave
> Cave Consulting LLC
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