Displaying 20 results from an estimated 1000 matches similar to: "Optimization problem: selecting independent rows to maximize the mean"
2011 Apr 27
6
Assignments inside lapply
Dear all I would like to ask you if an assignment can be done inside a lapply statement.
For example
I would like to covert a double nested for loop
for (i in c(1:dimx)){
for (j in c(1:dimy)){
Powermap[i,j] <- Pr(c(i,j),c(PRX,PRY),f)
}
}
to something like that:
ij<-expand.grid(i=seq(1:dimx),j=(1:dimy))
unlist(lapply(1:nrow(ij),function(rowId) { return
2010 Mar 12
1
Length as fun.aggregate in cast function of reshape package: unexpected error
Dear Everyone,
I am having problems with use of the reshape package's cast function using length as an aggregating function.
Unexpectedly, I receive the error: 2 arguments passed to 'length' which requires 1
I don't understand this at all - the data I'm using is very simple, and appears almost identical to that used in the
ChickWeight example in the package. The problem can
2010 Feb 08
1
R ggplot2 legend text left justify
In ggplot2 how do you justify the legend text ?
In the example below the opts(legend.text = theme_text(size =
9,hjust=0)) changes the size of the text OK but it remains right
justified.
> mydata=data.frame(RowID=c("A","B","C"),Name=c("long long long long
long name","short name ","medium medium name"),Speed=c(100,140,120))
>
2012 Aug 17
2
How can we compare corresponding values of x and y (first value of x exacly matches with the first value of y)?
df <- data.frame (
"RowId" = 4:7,
"x"=c("1_1", "2_2", "3_3", "3_3"),
"y"=c("1_1", "3_3", "2_2", "3_3")
)
How can we compare corresponding values of x and y (first value of x exacly matches with the first value of y)?
If they were not matced
2020 Sep 24
1
How to use `[` without evaluating the arguments.
Hello R-devel,
I am currently attempting to implement an API similar to data.table wherein single bracket subsetting can accept an unquoted expression to be evaluated in the context of my object.
A simple example from the data.table package looks like this:
DT <- data.table(col1 = c('a', 'b', 'c'), col2 = c('x', 'y', 'z'))
DT[col1 ==
2012 Mar 07
1
SELECT CASE in RODBC
Hi all,
I have a problem with a variable created by a SELECT CASE statement. See
the code below.
I would like the variable "event" to be a character variabel as I want to
UNION my two SELECTs - and the "event"-variable is a character variable in
the first SELECT result.
I have tried different ways:
* used ' ' in stead of " " around the string I want as the
2006 Jan 16
8
AJAX + Table.
Hello all.
I am trying ot load table rows using AJAX based on a search. The
following code results in:
1. Firefox renders correctly (Multiple rows inserted into page).
2. Opera renders the entire returned string in one <td> by the looks of
it (Bunched up under first header, the <> tags arne''t visible)
3. IE6 does nothing....great ;)
This is driving me nuts so any help
2010 Mar 31
2
Simplifying particular piece of code
Hello, everyone
I have a piece of code that looks like this:
mrets <- merge(mrets, BMM.SR=apply(mrets, 1, MyFunc, ret="BMM.AV120",
stdev="BMM.SD120"))
mrets <- merge(mrets, GM1.SR=apply(mrets, 1, MyFunc, ret="GM1.AV120",
stdev="GM1.SD120"))
mrets <- merge(mrets, IYC.SR=apply(mrets, 1, MyFunc, ret="IYC.AV120",
2013 Apr 26
1
Stratified Random Sampling Proportional to Size
Hello R Experts,
I kindly request your assistance on figuring out how to get a stratified random sampling proportional to 100.
Below is my r code showing what I did and the error I'm getting with sampling::strata
# FIRST I summarized count of records by the two variables I want to use as strata
Library(RODBC)
library(sqldf)
library(sampling)
#After establishing connection I query the data
2012 Jun 01
4
[PATCH v3] virtio_blk: unlock vblk->lock during kick
Holding the vblk->lock across kick causes poor scalability in SMP
guests. If one CPU is doing virtqueue kick and another CPU touches the
vblk->lock it will have to spin until virtqueue kick completes.
This patch reduces system% CPU utilization in SMP guests that are
running multithreaded I/O-bound workloads. The improvements are small
but show as iops and SMP are increased.
Khoa Huynh
2012 Jun 01
4
[PATCH v3] virtio_blk: unlock vblk->lock during kick
Holding the vblk->lock across kick causes poor scalability in SMP
guests. If one CPU is doing virtqueue kick and another CPU touches the
vblk->lock it will have to spin until virtqueue kick completes.
This patch reduces system% CPU utilization in SMP guests that are
running multithreaded I/O-bound workloads. The improvements are small
but show as iops and SMP are increased.
Khoa Huynh
2013 Feb 11
2
How to plot doubles series with different location using plotCI
Dear list
members,
I would
like to create two series of plotted mean values and error bars, yet with
different locations along the x-axis.
Plotting of
first series using plotCI with the standard arguments goes without any problem.
However I do not succeed to add the second series in the same plot, which
should be horizontally shifted from the first series along the x-axis. The “add=TRUE”
2002 Mar 01
3
calculating std err (SEM)?
Is there a "canned" function in R for finding the standard error of the
mean? I have tried
> sem <- function(x) c(mean =mean(x),
+ SEM = stdev(x)/sqrt(length(x)))
> sem(pnet.lai)
Error in sem(pnet.lai) : couldn't find function "stdev"
It looks like there is no stdev function in R
Thanks,
Kirk
Kirk R. Wythers email: kwythers at umn.edu
University of
2010 Apr 21
2
Maximum Likelihood Estimation in R
Dear R-Help,
I also send the following post by e-mail to you, however I try to post it
here aswell. My name is Henrik and I am currently trying to solve a Maximum
Likelihood optimization problem in R. Below you can find the output from R,
when I use the "BFGS" method:
The problem is that the parameters that I get are very unreasonable, I would
expect the absolute value of each
2002 Feb 22
2
errors in integrate function?
I have been trying the integrate function in R, a function which would be
very useful for a current project of mine. But I am encountering errors
integrating the one function I have tried. The function to be integrated is
a product of a gamma demsity and a normal density:
gamma.by.normal_function(y,x,shape,scale,stdev)
return( dgamma(y,shape=shape,scale=scale)*
2010 Nov 04
5
ggplot output
Dear All,
I have this script:
dat <- data.frame(Month = hstat$Date,C_avg = hstat$C.avg,C_stdev =
hstat$C.stdev)
ggplot(data = dat, aes(x = Month, y = C_avg, ymin = C_avg - C_stdev, ymax =
C_avg + C_stdev)) +
geom_point() +
geom_line() +
geom_errorbar()
dat <- data.frame(Month = hstat$Date,K_avg = hstat$K.avg,K_stdev =
hstat$K.stdev)
ggplot(data = dat, aes(x = Month, y = K_avg,
2006 Oct 26
4
Header of dataframe
Hi
I am fairly new to R and I would appreciate some help to hopefully a
trivial problem.
I created a function:
summary.aggregate <- function(y, ...)
{
temp.mean <- aggregate(y, FUN=mean, ...)
temp.sd <- aggregate(y, FUN=sd, ...)
temp.length <- aggregate(y, FUN=length, ...)
temp <- data.frame(cbind(mean=temp.mean$x,stdev=temp.sd$x,n=temp.length$x))
}
this outputs e.g.:
2009 Sep 28
2
probability density function for maximum values in repeated finite samples from a normal distribution??
this is probably not really a R specific question, if so apologies for
off-topic posting:
I'm interested in the probability density function of the maximum values
from repeated samples of size N from a normal distribution:
smp <- rnorm(N, meanval, stdev)
with some mean 'meanval' and standard deviation 'stdev'.
I would like to know what is the frequency distribution of
2017 Oct 10
2
small files performance
2017-10-10 8:25 GMT+02:00 Karan Sandha <ksandha at redhat.com>:
> Hi Gandalf,
>
> We have multiple tuning to do for small-files which decrease the time for
> negative lookups , meta-data caching, parallel readdir. Bumping the server
> and client event threads will help you out in increasing the small file
> performance.
>
> gluster v set <vol-name> group
2008 Sep 05
2
typo in cov()? var() fails on NA in R 2.7.2 but not R 2.6.1
I recently started using R 2.7.2, and noticed a surprising change in
the behavior of var() on NA data:
R 2.6.1 (Patched), 2007-11-26, svn.rev 43541, x86_64-unknown-linux-gnu:
> stdev(rep(NA,3), na.rm=F)
[1] NA
> stdev(rep(NA,3), na.rm=T)
[1] NA
> var(rep(NA,3), na.rm=T, use="complete.obs")
[1] NA
R 2.7.2 (Patched), 2008-09-02, svn.rev 46491,