Displaying 20 results from an estimated 5000 matches similar to: "Permutations (summary)"
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
2010 Apr 24
2
multiple paired t-tests without loops
I am new to R and I suspect my problem is easily solved, but I haven't
been able to figure it out without using loops. I am trying to
implement Blair & Karniski's (1993) permutation test. I've included a
sample data frame below. This data frame represents the conditional
means (C1, C2) for 3 subjects in 2 consecutive samples of a continuous
data set (e.g. ERP waveform).
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
2017 Jun 21
0
Permutations in RDA for repeated measures, using how()
Dear all,
I am using RDA to study plant communities in various land uses (variable LU with values M, U, etc.). For each land use, I sample 3 to 5 fields (M1, M2, U1, U2, etc). I make 5 measurements for both plant communities and environmental variables in each field.
I repeat the process every 6 months to study the effect of time and season (D16 for dry season 2017, R16 for rainy season 2016,
2008 Jan 25
1
increasing speed for permutations of glm
Dear R Programmers,
I am trying to run a Poisson regression on all pairs of variables in a data
set and
obtain the permutation distribution. The number of pairs is around 100000.
It seems my code will take weeks to run, unless I try something else.
Could you give me any suggestions on how to improve the speed of the
code below, or any general suggestions on how I may accomplish this task.
Thanks
2009 Nov 12
2
A combinatorial optimization problem: finding the best permutation of a complex vector
Hi,
I have a complex-valued vector X in C^n. Given another complex-valued vector Y in C^n, I want to find a permutation of Y, say, Y*, that minimizes ||X - Y*||, the distance between X and Y*.
Note that this problem can be trivially solved for "Real" vectors, since real numbers possess the ordering property. Complex numbers, however, do not possess this property. Hence the
2002 Jan 16
2
exhaustive permutations
Hello R-help Readers
I'm currently in the process of trying to write a permutation test
procedure for looking at differences between groups with a multivariate
data set (something equivalent to ANOSIM - analaysis of similarities for
those familiar with this test). As with other permutation tests, for
cases where there are large numbers of possible permutations, randomly
sampling from these
2009 Dec 18
2
Generating permutations that always include one specific element
Dear R community,
I am trying to create a matrix of permutations of a vector:
bands <- c("AL", "B", "DB", "DG", "G", "K", "LB", "LG", "MG", "O", "P",
"PI", "PK", "PU", "R", "V", "W", "Y")
Each permutation must be 4
2008 Apr 06
3
Multiset Permutations
Dear R users,
I want to perform an exact permutation of multisets. I have looked at the
coin package, but it doesn't seem to offer what I am looking for. I want to
perform permutations (exact - without duplications) on multisets of scalars
(e.g., the multiset 0,0,1,2,2). I want to output all the possible
permutations into a data frame so that each multiset permutation occupies a
row (or
2008 Apr 02
0
Exact Permutation test
R users,
Is it possible to do 'exact' permutation tests in R? If I run a perm.test or
permutation.test.discrete on a data set that has, for example, 720 possible
permutations, will that test permute ALL of those possible permutations, or
will it just permute 720 random permutations (thus allowing some
possibilities to repeat and some not to be permuted at all)?
I'm a little confused
2017 Dec 08
0
Curiously short cycles in iterated permutations with the same seed
Hi Boris,
Do a search on "the order of elements of the symmetric group". (This search
will also turn up homework questions and solutions.) You will understand
why you are seeing this once you understand how a permutation is decomposed
into cycles and how the order relates to a partition of n (n=10 in your
case).
Enjoy!
Eric
On Fri, Dec 8, 2017 at 6:39 AM, Boris Steipe <boris.steipe
2004 Apr 17
0
nlme - sum of squares - permutation test
Hi,
1/ I wonder why a anova.lme on a single lme object does not print the sum of squares (as expected from the help: "a data frame with the sums of squares, numerator degrees of freedom, denominator
degrees of freedom, F-values, and P-values").
Example:
> fm2 <- lme(distance ~ age + Sex, data = Orthodont, random = ~ 1)
> anova(fm2)
numDF denDF F-value p-value
2007 May 30
0
manova permutations and pair-wise contrasts
Hi,
I have a function for doing permutation tests for Manovas, written
with the help of folks here on the list. It seems to work ok, and I've
found that there is indeed a significant difference among groups in my
analysis. I want to follow up on this by testing for which pairs of
groups are significantly different. Reasoning that since Wilks Lambda
is a generalization of the Hotelling T test,
2008 Nov 14
1
Generating unique permutations of a vector
Hi all,
I try to generate sets of strategies that contain probability
distributions for a defined number of elements, e.g. imagine an
animal that can produce 5 different types of offspring and I want to
figure out which percentage of each type it should produce in order to
maximize its fitness. In order to do so, I need to calculate the fitness
for all potential strategies. As an example, if I
2006 Aug 21
0
Fw: Permutations with replacement
My apologies, I forgot to CC: to the list on my previous communication
with Daniel.
Jesse
----- Forwarded by Jesse Albert Canchola/EMVL/DIAG/US/BAYER on 08/21/2006
10:50 AM -----
Jesse Albert Canchola/EMVL/DIAG/US/BAYER
08/21/2006 09:36 AM
To
"Daniel Nordlund" <res90sx5 at verizon.net>
cc
Subject
RE: [R] Permutations with replacement
Thanks, Daniel. I need to enumerate
2007 Oct 02
1
permutations of a binary matrix with fixed margins
J?r?me,
As a first attempt, how about the function below. It works (or not) by
randomly sorting the rows and columns, then searching the table for
"squares" with the corners = matrix(c(1,0,0,1),ncol=2) and subtracting them
from 1 to give matrix(c(0,1,1,0),ncol=2) (and vice versa). Randomized
matrices can be produced as a chain where each permutation is seeded with
the previous one.
2008 Feb 21
1
Permutation Test
Dear R users,
i am fairly new to R and am having trouble creating code to solve a problem.
I've searched the list, combed Crawley's 'R book' and several others, but
can't quite find what i want.
I want to generate permutations of various 'blocks' of 14 numbers. Each
number within a block is a character state for a particular biological
taxon. In the example below, for
2010 Jan 14
2
Fixed size permutations
I'm using functions to return a matrix of all permutations of a
specified size from a larger list for predictor selection.
For each predictor size I use a seperate function like this:
bag2 <- function(n) {
rl <- c()
for (i1 in seq(n)) {
for (i2 in seq(n)) {
if (length(unique(c(i1,i2)))==1) {next}
rl <- cbind(rl,matrix(c(i1,i2)))
}
}
2017 Dec 08
2
Curiously short cycles in iterated permutations with the same seed
I have noticed that when I iterate permutations of short vectors with the same seed, the cycle lengths are much shorter than I would expect by chance. For example:
X <- 1:10
Xorig <- X
start <- 112358
N <- 10
for (i in 1:N) {
seed <- start + i
for (j in 1:1000) { # Maximum cycle length to consider
set.seed(seed) # Re-seed RNG to same initial state
X <- sample(X)
2010 Jan 19
1
restricted permutations in permtest()?
Hallo List,
I'm trying to implemement a restricted permutation scheme in permutest(). More
precisely I have dependence in my data that should be allowed for in the
permutation - I simulated the problem in the example of the vegan documentation
p.24:
library(vegan)
data(varespec)
## Bray-Curtis distances between samples
dis <- vegdist(varespec)
## First 16 sites grazed, remaining 8 sites