It did take me a good night's sleep to understand it. I was stuck with
the exact same question but I see now how the remaining balls are
shared among all 8 urns (therefore cases with 11, 12, 13, ... 17 balls
are also dealt with).
Thanks again,
baptiste
2010/1/12 Rolf Turner
[mailto:r-help-boun...@r-
project.org] On Behalf Of Brian Diggs
Sent: Thursday, December 31, 2009 3:08 PM
To: baptiste auguie; David Winsemius
Cc: r-help
Subject: Re: [R] expand.grid game
baptiste auguie wrote:
2009/12/19 David Winsemius dwinsem...@comcast.net:
On Dec 19, 2009, at 9:06 AM
] On Behalf Of Brian Diggs
Sent: Thursday, December 31, 2009 3:08 PM
To: baptiste auguie; David Winsemius
Cc: r-help
Subject: Re: [R] expand.grid game
baptiste auguie wrote:
2009/12/19 David Winsemius dwinsem...@comcast.net:
On Dec 19, 2009, at 9:06 AM, baptiste auguie wrote:
Dear list
Message-
From: baptiste auguie [mailto:baptiste.aug...@googlemail.com]
Sent: Tuesday, January 12, 2010 12:20 PM
To: Greg Snow
Cc: r-help
Subject: Re: [R] expand.grid game
Nice --- am I missing something or was this closed form solution not
entirely trivial to find?
I ought to compile
On 13/01/2010, at 9:19 AM, Greg Snow wrote:
How trivial is probably subjective, I don't think it is much above
trivial. I would not have been surprised to see this question on
an exam in my undergraduate (300 or junior level) probability
course (the hard part was remembering the details
...@googlemail.com]
Sent: Tuesday, January 12, 2010 12:20 PM
To: Greg Snow
Cc: r-help
Subject: Re: [R] expand.grid game
Nice --- am I missing something or was this closed form solution not
entirely trivial to find?
I ought to compile the various clever solutions given in this thread
someday, it's
baptiste auguie wrote:
2009/12/19 David Winsemius dwinsem...@comcast.net:
On Dec 19, 2009, at 9:06 AM, baptiste auguie wrote:
Dear list,
In a little numbers game, I've hit a performance snag and I'm not sure
how to code this in C.
The game is the following: how many 8-digit numbers have
Hi
library(partitions)
jj - blockparts(rep(9,8),17)
dim(jj)
gives 318648
HTH
rksh
baptiste auguie wrote:
Dear list,
In a little numbers game, I've hit a performance snag and I'm not sure
how to code this in C.
The game is the following: how many 8-digit numbers have the sum of
their
Wow!
system.time({
all = blockparts(rep(9,8),17)
print( dim(all[,all[1,]!=0])[2] ) # remove leading 0s
})
## 229713
user system elapsed
0.160 0.068 0.228
In some ways I think this is close to Hadley's suggestion, though I
didn't know how to implement it.
Thanks a lot to everybody who
Hello again everybody.
I fired off my reply before reading the correspondence about
the leading zeros.
You can also assume that there is at least one block
at the leading position, [so that position can take 0,1,2,...,8 additional
blocks] and distribute the remaining 16 blocks amongst all 8
I wonder whether this answers Baptiste's question as asked.
1: An 8-digit number can have some digits equal to 0;
see Baptiste's comment maxi - 9 # digits from 0 to 9
2: According to the man-page fror blockparts in partitions,
all sets of a=(a1,...,an) satisfying Sum[ai] = n subject
to
OOPS!! See correction below!
On 21-Dec-09 08:45:13, Ted Harding wrote:
I wonder whether this answers Baptiste's question as asked.
1: An 8-digit number can have some digits equal to 0;
see Baptiste's comment maxi - 9 # digits from 0 to 9
2: According to the man-page fror blockparts in
Hi Ted.
you've found a bug in the documentation for blockparts().
It should read 0 = ai = yi. I'll fix it before the next
major release (which will include sampling without replacement from
a multiset, Insha'Allah).
Best wishes
rksh
(Ted Harding) wrote:
I wonder whether this answers
Dear list,
In a little numbers game, I've hit a performance snag and I'm not sure
how to code this in C.
The game is the following: how many 8-digit numbers have the sum of
their digits equal to 17?
The brute-force answer could be:
maxi - 9 # digits from 0 to 9
N - 5 # 8 is too large
test - 17
On Dec 19, 2009, at 9:06 AM, baptiste auguie wrote:
Dear list,
In a little numbers game, I've hit a performance snag and I'm not sure
how to code this in C.
The game is the following: how many 8-digit numbers have the sum of
their digits equal to 17?
The brute-force answer could be:
maxi -
2009/12/19 David Winsemius dwinsem...@comcast.net:
On Dec 19, 2009, at 9:06 AM, baptiste auguie wrote:
Dear list,
In a little numbers game, I've hit a performance snag and I'm not sure
how to code this in C.
The game is the following: how many 8-digit numbers have the sum of
their digits
I hope I have missed a better way to do this in R. Otherwise, I
believe what I'm after is some kind of C or C++ macro expansion,
because the number of loops should not be hard coded.
Why not generate the list of integers that sum to 17, and then mix
with 0s as appropriate?
Hadley
--
On Dec 19, 2009, at 1:36 PM, baptiste auguie wrote:
2009/12/19 David Winsemius dwinsem...@comcast.net:
On Dec 19, 2009, at 9:06 AM, baptiste auguie wrote:
Dear list,
In a little numbers game, I've hit a performance snag and I'm not
sure
how to code this in C.
The game is the
Hi,
Thanks for the link, I guess it's some kind of a classic game. I'm a
bit surprised by your timing, my ugly eval(parse()) solution
definitely took less than one hour with a machine not so different
from yours,
system.time( for (i in 1079:1179) if (sumdigits(i)==17) {idx-c(idx,i)})
This problem does yield some interesting and unexpected distributions.
Here is another, the number of positive cases as a function of number
of digits (8 in the original question) and of test value (17).
maxi - 9
N - 5
test - 17
foo - function(N=2, test=1){
sum(rowSums(do.call(expand.grid,
On Dec 19, 2009, at 2:28 PM, baptiste auguie wrote:
Hi,
Thanks for the link, I guess it's some kind of a classic game. I'm a
bit surprised by your timing, my ugly eval(parse()) solution
definitely took less than one hour with a machine not so different
from yours,
system.time( for (i in
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