Displaying 20 results from an estimated 10000 matches similar to: "Mod function?"
2006 Dec 10
4
sample "n" random positions from a matrix
Hi there,
I have a binary matrix (dim 100x100) filled with values 0 and 1. I need select a record "n" positions of that matrix when values are 1. How can I do that?
Thanks for all,
Miltinho
Brazil
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2005 Jan 12
2
?"=" (Windows) (PR#7504)
?"=", ?"==", ?"!=", ?">=", and ?"<=" sends me to the documentation for
?help on Windows, while returning the correct documentation on Linux.
Robert
> version
_
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor
2006 Dec 31
4
Does SQL group by have a heavy duty equivalent in R
I have hundreds of humans who have undergone SNP genotyping at hundreds of
loci. Some have even undergone the procedure twice or thrice (kind of an
internal control).
So obviously I need to find those replications, and confirm that the results
are the same. If there is discordance then I need to address it.
I tried to use the aggregate function
nr.attempts
2009 Oct 13
7
lapply() reccursively
Hi all,
I was wondering whether it is possible to use the lapply() function
to alter the value of the input, something in the spirit of :
a1<-runif(100)
a2<-function(i){
a1[i]<-a1[i-1]*a1[i];a1[i]
}
a3<-lapply(2:100,a2)
Something akin to a for() loop, but using the lapply() infrastructure.
I haven't been able to get rapply() to do this.
The reason is that the "real"
2006 May 12
4
bitwise addition
Hello all again,
I want to do bitwise addition in R. I am trying to generate a matrix
0000
0001
0010
....
....
1111
I know the other ways of generating this matrix but I need to look at bitwise
addition.
Any suggestions???
thanks a lot
Nameeta
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2010 Jul 07
3
How do I test against a simple null that two regressions coefficients are equal?
Hi there,
I run two regressions:
y = a1 + b1 * x + e1
y = a2 + b2 * z + e2
I want to test against the null hypothesis: b1 = b2. How do I design the test?
I think I can add two equations together and divide both sides by 2:
y = 0.5*(a1+a2) + 0.5*b1 * x + 0.5*b2 * z + e3, where e3 = 0.5*(e1 + e2).
or just y = a3 + 0.5*b1 * x + 0.5*b2 * z + e3
If I run this new regression, I can test against
2005 Mar 09
3
R-2.0.1 Gentoo g77 problem
Hello,
I use Gentoo and I can't get R 2.0.1 to compile. I used the portage system, Gentoo's source package sytem, and after it uncompresses the source to R, it says that I don't have a fortran compiler. It told me to use f77 flag and re-emerge gcc, which I did with the f77 and fortran flags, but it still won't compile. Does anyone have any ideas? I suspect that gcc has changed
2006 Dec 14
5
persistant: Matlab->R
Dear list members,
Could anyone tell me if there is an equivalent of the Matlab declaration 'persistant' in R?
Thank you very much,
Bernard Gregorry.
(Matlaber converted to R).
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2008 May 27
4
help with simple function
I have a matrix of frequency counts from 0-160.
x<-as.matrix(c(0,1,0,0,1,0,0,0,1,0,0,0,0,1))
I would like to apply a function creating a new column (x[,2])containing
values equal to:
a) log(x[m,1]) if x[m,1] > 0; and
b) for all x[m,1]= 0, log(next x[m,1] > 0 / count of preceding zero values
+1)
for example, x[1,2] should equal log(x[2,1]/2) = log(1/2) = -0.6931472
whereas x[3,2] should
2008 Dec 11
3
check if a certain ... argument has been passed on to my user-defined function
Hi,
How can I check if a certain ... argument has been passed on to my
user-defined function or not?
foo <- function(data, ...)
{
### here I want to check whether xlab was passed with the ... arguments
### or if the ... arguments did not contain an xlab argument
}
I tried missing(xlab) , exists(xlab) and several other things but did not
find a solution.
TIA,
Mark
2008 Jan 23
4
image question
Hi,
I have a question regarding the image function. Is there a way to specify a
separate color set for each column in the matrix?
TIA,
ajar.
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2007 Aug 04
2
Mixture of Normals with Large Data
All:
I am trying to fit a mixture of 2 normals with > 110 million observations. I
am running R 2.5.1 on a box with 1gb RAM running 32-bit windows and I
continue to run out of memory. Does anyone have any suggestions.
Thanks so much,
Tim
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2008 Dec 09
2
Better way to find distances between points in a set?
I was playing around a bit to see how I could find the two points in a
set of points (or ordered pairs) furthest from each other.
Here's what I did:
1) created a Nrow by 2col matrix, so each row contains an x,y coordinate
pair.
2) fed the matrix to a nested mapply (cv is my matrix):
mapply(function(k,l) mapply(function(x,y,a,b)
+
2007 Feb 22
4
Crosstabbing multiple response data
Using R version 2.4.1 (2006-12-18) on Windows, I have a dataset which resembles this:
id att1 att2 att3
1 1 1 0
2 1 0 0
3 0 1 1
4 1 1 1
ratings <- data.frame(id = c(1,2,3,4), att1 = c(1,1,0,1), att2 = c(1,0,0,1), att3 = c(0,1,1,1))
I would like to get a cross tab of counts of co-ocurrence, which might resemble this:
2009 Nov 16
3
Cluster analysis: hclust manipulation possible?
I am doing cluster analysis [hclust(Dist, method="average")] on
data that potentially contains redundant objects. As expected,
the inclusion of redundant objects affects the clustering result,
i.e., the data a1, = a2, = a3, b, c, d, e1, = e2 is likely to
cluster differently from the same data without the redundancy,
i.e., a1, b, c, d, e1. This is apparent when the outcome is
visualized
2011 Jan 24
2
Help with expression
I have a problem with expressions. I am trying to create a title where
the parameter of interest is displayed as a Greek character. Which
parameter is being considered is stored in a character variable.
As an example, if I have
param <- "alpha"
and then do
plot(0, 0, main = bquote(Parameter==.(param)))
then in the title I get "Parameter = alpha",
whereas I want the
2009 Feb 16
2
Using eval in multinom argument
Hi,
I am having difficulty entering a 'programmable' argument into the multinom function from the nnet package. Interactively, I can get the function to work fine by calling it this way:
z1=multinom(formula = class.ind(grp[-outgroup])~ (PC1 + PC2 + PC3), data=data.frame(scores))
However I need to be able to change the number of variables I am looking for in 'scores' and so am
2008 Oct 30
3
why does sample(x, n) give the same n items in every separate runs?
Hello R users,
I have gene expression data of two groups of genes (large and small). Gene expression intensities of those genes are classified into 1 to 10 levels. What I want is to make a random set of genes that have the same levels as the small group from large group using sample().
I used smallvec to hold the number of genes in each levels (1 to 10) for small group, largevec for large group.
2006 Dec 12
1
Calculating AICc using conditional logistic regression
I have a case-control study that I'm analysing using the conditional
logistic regression function clogit from the survival package.
I would like to calculate the AICc of the models I fit using clogit.
I have a variety of scripts that can calculate AICc for models with a
logLik method, but clogit does not appear to use this method.
Is there a way I can calculate AICc from clogit in R?
Many
2006 Oct 03
1
latex expression
Dear All:
I try to use latex expression in legend, but I am not very clear on the
detail rules in R. I remeber there is a R help page list all rules and many
examples, but I forget what should I type (?xxx) to get this help page.
Could you please remind me which function should I type?
Thanks
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