Displaying 20 results from an estimated 10000 matches similar to: "Permutation problem"
2006 Oct 13
5
combinatorics
Hi
How do I generate all ways of ordering sets of indistinguishable items?
suppose I have two A's, two B's and a C.
Then I want
AABBC
AABCB
AACBC
ABABC
. . .snip...
BBAAC
. . .snip...
CBBAA
[there are 5!/(2!*2!) = 30 arrangements. Note AABBC != BBAAC]
How do I do this?
--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14
2007 Oct 06
1
Question about Distinguishable Permutation
Hi,
How can I list all possilities of Distinguishable Permutation by R? For example, N=6, n1=n2=n3=2, the total possible answers are 6!/(2!2!2!)=90.
Please help me.
Thank you So much.
____________________________________________________________________________________¡A
2006 Mar 06
1
combinatorics again
Hi
I want to enumerate all vectors of length "J", whose elements are
integers in the range 1 to S, without regard to ordering.
With J=S=3, the combinations are as follows:
[,1] [,2] [,3]
[1,] 1 1 1
[2,] 1 1 2
[3,] 1 1 3
[4,] 1 2 2
[5,] 1 2 3
[6,] 1 3 3
[7,] 2 2 2
[8,] 2 2 3
[9,] 2
2006 May 08
3
Non repetitive permutations/combinations of elements
Hello all,
I am trying to create a matrix of 1s and -1s without any repetitions for a
specified number of columns.
e.g. 1s and -1s for 3 columns can be done uniquely in 2^3 ways.
-1 -1 -1
-1 -1 1
-1 1 -1
-1 1 1
1 -1 -1
1 -1 1
1 1 -1
1 1 1
and for 4 columns in 2^4 ways and so on.
I finally used the function combn([0 1],3) that I found at the following link
2007 Nov 19
2
All nonnegative integer solution
Dear all,
Is there any method in R to find all possible nonnegative integer
solutions to the linear equation with unit coefficients as follow:
X1+X2+...+Xk=N
Thank you,
Amin Zollanvari
2004 Jul 13
3
(no subject)
Dear R users,
First of all, thanks for the incredibly fast answers and help of Rolf,
Marc and Robert.
Yes, I noticed that it was a lot of permutacions, but my intention was to
make this process automatic and take only 5.000 - 10.000 permutations.
Therefore, I wanted only to take that "interesting permutations" with "some
information" [inter-block permutations].
The
2005 Nov 17
3
changing figure size in Sweave
Hi
In Sweave, how does one change the size of the plots?
I tried using a hook:
<<echo=FALSE, print=FALSE, fig=TRUE>>=
options(SweaveHooks=list(fig=function() ps.options(width=1)))
library(graphics)
pairs(iris)
@
but this didn't change the size of the figure. How to make the
figures a
different size?
--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre,
2006 Sep 13
3
functions and strings
Hi
If
string <- "xyz"
f <- function(x){1 + sin(cos(x)) + exp(x^2)}
How do I manipulate "string" and f() to give the string
"1 + sin(cos(xyz)) + exp(xyz^2)"
?
--
Robin Hankin
Uncertainty Analyst
National Oceanography Centre, Southampton
European Way, Southampton SO14 3ZH, UK
tel 023-8059-7743
2004 Jul 13
12
Permutations
Dear R users,
I?m a beginner user of R and I?ve a problem with permutations that I don?t
know how to solve. I?ve 12 elements in blocks of 3 elements and I want only
to make permutations inter-blocks (no intra-blocks) (sorry if the
terminology is not accurate), something similar to:
1 2 3 | 4 5 6 | 7 8 9 | 10 11 12 ----------1st permutation
1 3 2 | 4 5 6 | 7 8 9 | 10 11 12 NO
- -
3 2 1
2008 Mar 26
5
S4 slot with NA default
Hi
How do I specify an S4 class with a slot that is potentially numeric,
but NA
by default? I want the slot to be NA until I calculate its value
(an expensive operation, not needed for all applications). When
its value is
known, I will create a new object with the correct value inserted in
the slot.
I want "NA" to signify "not known".
My attempt fails because
2006 Feb 22
3
elements that appear only once
Hi.
I have a factor and I want to extract just those elements that appear
exactly once.
How to do this?
Toy example follows.
> a <- as.factor(c(rep("oak",5) ,rep("ash",1),rep("elm",1),rep
("beech",4)))
> a
[1] oak oak oak oak oak ash elm beech beech beech beech
Levels: ash beech elm oak
> table(a)
a
ash beech elm oak
2006 Jul 27
4
inserting rows into a matrix
Hi
I have a little vector function that takes a vector A of strictly
positive integers
and outputs a matrix M each of whose columns is the vector, modified in
a complicated combinatorical way.
Now I want to generalize the function so that A can include zeroes.
Given A,
I want to strip out the zeroes, pass it to my function, and pad M
with rows at positions corresponding to the zeroes
2007 Mar 19
3
character to numeric conversion
Hi.
Is there a straightforward way to convert a character string
containing comma-delimited
numbers to a numeric vector?
In my application, I use
system(executable.string, intern=TRUE)
which returns a string like
"[0.E-38, 2.096751179214927596171268230,
3.678944959657480671183123052, 4.976528845643001020345216157,
6.072390165503099343887569007, 7.007958550337542210168866070,
2005 Jan 07
1
Visualizing complex analytic functions using domain coloring
Hi
has anyone coded up domain colouring for visualizing complex analytic
functions
(such as elliptic functions)?
[
the idea is to depict a complex function f(z) using a filled.contour()
variant
in which the hue is given by Arg(f(z)), and the saturation by Mod(f(z)).
]
--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
European Way, Southampton SO14 3ZH, UK
tel
2005 Jan 05
4
output from table() in matrix form
Hi
How do I get the output from table() in matrix form?
If I have
R> table(c(1,1,1,1,2,20))
1 2 20
4 1 1
I want
[,1] [,2] [,3]
[1,] 1 2 20
[2,] 4 1 1
The problem is that names(table) is a vector of characters and I need
the numeric values.
I am using
R> rbind(as.integer(names(x)),x)
I thought tabulate() might be better as it takes an
2007 Jan 16
5
"[[" gotcha
The following gotcha caught me off-guard just now.
I have two matrices, a and b:
a <- matrix(1,3,3)
b <- matrix(1,1,1)
(note that both "a" and "b" are matrices).
I want them in a list:
> B <- NULL
> B[[1]] <- a
> B[[2]] <- b
> B
[[1]]
[,1] [,2] [,3]
[1,] 1 1 1
[2,] 1 1 1
[3,] 1 1 1
[[2]]
[,1]
[1,] 1
2006 May 16
3
sparklines
I am fairly new to R so I don;t know much about manipulating it yet.
I would like to make some sparklines <http://www.edwardtufte.com/
bboard/q-and-a-fetch-msg?msg_id=0001OR&topic_id=1> using R. I have th
pre-compiled R for MacOS on intel. Any help would be greatly
appreciated.
Thanks
Robert
2005 Jun 20
6
sweep() and recycling
Hi
I had a hard-to-find bug in some of my code the other day, which I
eventually
traced to my misusing of sweep().
I would expect sweep() to give
me a warning if the elements don't recycle nicely, but
X <- matrix(1:36,6,6)
sweep(X,1,1:5,"+")
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 2 9 16 23 30 32
[2,] 4 11 18 25 27 34
[3,] 6 13 20 22
2006 Feb 28
2
lines() and recycled colours
Hi
?lines says
For 'type = "h"', 'col' can be a vector and will be recycled as
needed.
Why doesn't lines() recycle colours for other types?
If I type
> plot(0:1,0:1,type="n")
> lines(runif(11),runif(11),col=c("red","green"))
>
then all ten lines are red, with no warning given. Is there a reason
why
2006 Jul 25
2
pari/gp interface
Hi
I'm developing an R package that
needs to execute some code written in pari/gp.
I've used this before from an R package (elliptic) but the interface
is very
basic: the R function creates a string such as the following:
string <- echo ' ellwp ([ 2+0*I , 0+2*I ], 1+0*I )' | gp -q
And then
system(string)
returns the output from gp which then needs to be text processed