Displaying 20 results from an estimated 9000 matches similar to: "More efficient alternative to combn()?"
2010 Nov 17
1
efficient conversion of matrix column rows to list elements
Hi List,
I'm hoping to get opinions for enhancing the efficiency of the following
code designed to take a vector of probabilities (outcomes) and calculate a
union of the probability space. As part of the union calculation, combn()
must be used, which returns a matrix, and the parallelized version of
lapply() provided in the multicore package requires a list. I've found that
2012 Nov 16
1
pairing data using combn with criteria
Dear All,
I have a dataframe made up of individual beetles consisting of individual
number, family number, mother's family number, father's family number, and
sex of the beetle. I would like to pair up the individuals for breeding. I
would, however, like to avoid breeding beetles of the same sex (obviously),
the same family, and with the same mother's family or father's family,
2010 Apr 07
1
combn with factors
Dear list,
I have come across this issue:
combn(letters[1:5], 3)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] "a" "a" "a" "a" "a" "a" "b" "b" "b" "c"
[2,] "b" "b" "b" "c" "c" "d" "c"
2011 Oct 16
1
multicore combn
This is a 'rather than re-invent the wheel' post. Has anyone out there
re-written combn so that it can be parallelized - with multicore, snow, or
otherwise? I have a job that requires large numbers of combinations, and
rather than get all of the index values, then crank it through mclapply, I
was wondering if there was a way to just do this natively within a function.
Just curious.
2006 May 09
1
combn(n, k, ...) and all its re-inventions
It seems people are reinventing the wheel here:
The goal is to generate all combinations of 1:n of size k.
This (typically) results in a matrix of size k * choose(n,k)
i.e. needs O(n ^ k) space, hence is only applicable to
relatively small k.
Then alternatives have been devised to generate the combinations
"one by one", and I think I remember there has been a
quiz/challenge about 20
2009 Sep 21
2
Combine vectors in order to form matrixes with combn
Hello!
I've a problem with the combn function and a set of vector. I
would like to make a simple combination where, instead of scalars, i
would like to combine vector, in order to form matrixes.
In other
words, i have nineteen 6-items vectors (for example coef1-coef19), that
i would like to combine in n!/k!(n-k)! 6x6 matrixes.
I tried with a
code like this
mma <-
2011 Jan 10
1
Using combn
Dear list,
I want to apply the "table" function to every pair of variables in df
and the return should be a list.
setwd(123)
asd <- data.frame(a1=sample(1:4, 20, replace=TRUE),
a2=sample(1:4, 20, replace=TRUE),
a3=sample(1:4, 20, replace=TRUE),
a4=sample(1:4, 20, replace=TRUE))
with(asd, table(a1, a2))
with(asd, table(a1,
2008 Aug 15
2
Combination with repetition
Hi there! I can't find any information about creating combinations
with repetitions in R. The function combn() does create combinations,
but _without_ repetitions.
Here is what I need to do:
svIter <- 1000
xx <- matrix(rnorm(m*n), c(m, n))
sequence <- seq(range(xx)[1], range(xx)[2], length.out = svIter^(1/q))
expand.grid(secuence, secuence, .../q times/..., secuence)
That is,
2008 Feb 08
2
Applying lm to data with combn
http://www.nabble.com/file/p15359204/test.data.csv
http://www.nabble.com/file/p15359204/test.data.csv test.data.csv
Hi,
I have used apply to have certian combinations, but when I try to use these
combinations I get the error
[Error in eval(expr, envir, enclos) : object "X.GDAXI" not found]. being a
novice I donot understand that after applying combination to the data I cant
access
2013 Jan 24
2
Please help R error message "masked from 'package:utils':combn"
Hi
The message occurred from R, when I was selected of "optimization > block
diagonal Fhiser matrix" and used the attached file on PFIM.
Could you please advise me about the following message?
*****************************
Loading required pakage: combinat
Attaching package:'combinat'
The following object(s) are masked from 'package:utils':combn
2008 Mar 13
3
fast way to compare two matrices of combinations
I have a list (length 750), each element containing a vector of unique
strings (unique gene ids), with length up to ~40 (median 15). I want to
compile a matrix of all possible triplets and their frequency within
gene elements. Using combn and a lot of looping, I am accomplishing this
but it is VERY slow.
I've tried to figure out a way to vectorize this, using "match" and
2007 Mar 27
2
Newbie: Combn and scripting
Hello All,
I have just installed my R 2.4 (windows) as a test trying to load a data
frame and run combn() for each line into another file. How do I do this?
data.csv:
a,b,c,d
1,2,3.4
g,3,6,t
etc
x=data.csv, m=3
Thank you
Zam
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2007 Jan 19
2
combn implementation
Hi,
I was checking the source code to the function combn that "generates
all combinations of the elements of 'x' taken 'm' at a time.",
because I wished to modify it. I have a doubt about a statement.
This is the main loop.
._1 <- 1:1
nmmp1 <- n - m + ._1
while (a[1] != nmmp1) {
if (e < n - h) {
h <- ._1
e <-
2008 Dec 11
3
generate combination multiset (set with repetition)
Hi,
This has been asked before but not sufficiently answered from what I
could find. How do you create combinations
with repetitions (multisets) in R?
If I have
> set <- array(1:3)
And I want to choose all combinations of picking 2 numbers, I want to
get a print out like
[,1] [,2]
[1,] 1 1
[2,] 1 2
[3,] 1 3
[4,] 2 2
[5,] 2 3
[6,] 3 3
subsets(set,
2009 Apr 06
3
how to subsample all possible combinations of n species taken 1:n at a time?
Hello
I apologise for the length of this entry but please bear with me.
In short:
I need a way of subsampling communities from all possible communities of n
taxa taken 1:n at a time without having to calculate all possible
combinations (because this gives me a memory error - using
combn() or expand.grid() at least). Does anyone know of a function? Or can
you help me edit the
combn
or
2009 Nov 21
1
How to make a cartesian pairlist from a vector?
Hi,
I'm looking for a function that will take a list of columns or data.frame
and corvert it to cartesian pairlist. For example for this data.frame (see
below), I'd like to get a list of all possible pairs:
> sound
cs rs ns
7 5 2
4 5 4
6 3 1
8 4 1
6 4 2
6 7 1
2 2 5
9 2 5
how can I get this?
> mylist
((cs,rs), (cs,ns), (rs,ns))
2007 Apr 10
1
R CMD Rdconv drops sections: arguments, seealso, examples (PR#9606)
I've created a .Rd file (below), then converted that to .sgml using
R CMD Rdconv --type=Ssgm combn.Rd > combn.sgml
The output (shown below) is missing some of the sections:
arguments
seealso
examples
If instead I convert to .d (below), the same sections are missing,
and the "note" section is included but without the necessary newline.
2007 Apr 20
1
simply this loop?
Hi, anyone interested in this:
I tried to simply this loop with lapply or something but haven't figured it out:
mapt = c("203929_s_at", "203930_s_at", "203928_x_at", "206401_s_at")
mapt.combn <- lapply(1:4, function(i) combn(mapt, i))
out = list()
k = 1
for (i in 1:length(mapt.combn)){
for (j in 1:ncol(mapt.combn[[i]])){
out[[k]] =
2006 Oct 06
1
Sum of Bernoullis with varying probabilities
Hi Folks,
Given a series of n independent Bernoulli trials with
outcomes Yi (i=1...n) and Prob[Yi = 1] = Pi, I want
P = Prob[sum(Yi) = r] (r = 0,1,...,n)
I can certainly find a way to do it:
Let p be the vector c(P1,P2,...,Pn).
The cases r=0 and r=n are trivial (and also are exceptions
for the following routine).
For a given value of r in (1:(n-1)),
library(combinat)
Set <- (1:n)
2013 Sep 06
1
Importing function that is previously imported by other package
Dear developeRs,
I encounter the following problem: in the current version of my package
FrF2, certain calls to a functioni do not work when package combinat is
loaded, because function combn from combinat masks the function from
utils that my package uses.
I tried to solve this issue by importing function combn into the
namespace of FrF2; I don't need to export it, I just want to use it