Displaying 20 results from an estimated 2000 matches similar to: "matrix operations"
2005 Feb 25
4
Temporal Analysis of variable x; How to select the outlier threshold in R?
For a financial data set with large variance, I'm trying to find the
outlier threshold of one variable "x" over a two year period. I
qqplot(x2001, x2002) and found a normal distribution. The latter part of
the normal distribution did not look linear though. Is there a suitable
method in R to find the outlier threshold of this variable from 2001 and
2002 in R?
2010 Jul 17
2
cca in vegan (formula instead of community matrix data)
Dear List,
I tried to do cca based on species data and environmental variables (formula
instead of community data).
However, there was an error saying row sums must be >0.
I searched the previous related messages but found few solutions.
Please kindly help and thank you in advance.
code
This is vegan 1.17-3
Warning message:
package 'vegan' was built under R version 2.10.1
2010 Aug 17
2
Independent variables omitted in lm and glm
Dear List,
Some independent variable were missing in calculation using lm and glm
(gaussian).
(X= Y1+Y2+…..+Y16, Independent number: 16 variable)
However, those variables did work well in cor(X, Y) respectively.
str(dataframe) was also run to ensure that the variables were all numbers.
Moreover, the missing variables were different in lm and glm.
In lm, 3 factors were not taken into
2010 Aug 17
2
AIC in MuMIn
Hello,
I am using package MuMIn to calculate AIC for a full model with 10
explanatory variables.
Thanks in advance in sharing your experience.
Q1
In the AIC list of all models, each model is differentiated by model number.
Please kindly advise if it is possible to
find the corresponding explanatory variable(s) for the model number.
Q2 error message
I tried to display sub-model with only
2008 Oct 01
3
"tapply versus by" in function with more than 1 arguments
Hi. I searched the list and didn't found nothing similar to this. I simplified my example like below:
#I need calculate correlation (for example) between 2 columns classified by a third one at a data.frame, like below:
#number of rows
nr = 10
#the third column is to enforce that I need correlation on two variables only
dataf =
2005 Oct 07
1
returning a modified fix()-ed dataframe
Dear all,
In order to ease the transition from SPSS to R for some of my colleagues, I am
trying to create a function which would show the variables and their labels
(if those exist), using function "label" in package Hmisc.
A toy example would be this:
my.data <- data.frame(age=c(24,35,28), gender=c("Male", "Female", "Male"))
require(Hmisc)
2010 Jul 22
1
Updating a Data Frame
Hi,
I have a global data-frame in my R script.
At some point in my script, I want to update certain columns of this
data-frame by calling in an update function.
The function looks like this:
# get events data. This populates a global event data frame in the R-script
events <- getEvents(con, eventsFilePath)
# events has columns eventid, timeStamp, isSynchronized, timeDiff; with
millions of
2005 Mar 22
2
Error: Can not handle categorical predictors with more than 32 categories.
Hi All,
My question is in regards to an error generated when using randomForest
in R. Is there a special way to format the data in order to avoid this
error, or am I completely confused on what the error implies?
"Error in randomForest.default(m, y, ...) :
Can not handle categorical predictors with more than 32 categories."
This is generated from the command line:
>
2011 Nov 15
2
Models with ordered and unordered factors
Hello;
I am having a problems with the interpretation of models using ordered or
unordered predictors.
I am running models in lmer but I will try to give a simplified example
data set using lm.
Both in the example and in my real data set I use a predictor variable
referring to 3 consecutive days of an experiment. It is a factor, and I
thought it would be more correct to consider it ordered.
Below
2005 Mar 23
1
Gini's Importance Value Variable = Inf
Hi All,
In the script below, the importance measure for column 4 (ie
MeanDecreaseGini) indicated "Inf" for V7.
Running the getTree command showed that "V7" had been selected at least
twice in one of the trees for Random Forest. So the "Inf" command was
not generated as a result of dividing the sum of the decreases by 0.
Any suggestions on what may be causing the
2006 Mar 07
3
glm automation
Hello,
I have two problems in automating multiple glm(s) operations.
The data file is tab delimited file with headers and two columns. like
"ABC" "EFG"
1 2
2 3
3 4
dat <- read.table("FILENAME", header=TRUE, sep="\t", na.strings="NA",
dec=".", strip.white=TRUE)
dataf <- read.table("FILENAME", header=FALSE,
2009 Aug 24
1
Saving heatmaps as PDFs
Hi,
I'm trying to save heatmaps as PDFs. However, the PDF version of the
heatmaps (Heatmap_CAFvsTNF_run2.pdf) is blurred when compared to its
counterpart, which was saved manually by using the software
"Grab" (Heatmap_CAFvsTNF_run2.tiff).
-----R code--------
sample_output <- "stroma_run2"
filename <-
2009 Aug 12
2
Symbolic references - passing variable names into functions
Hello All,
I am trying to write a function which would operate on columns of a
dataframe specified in parameters passed to that function.
f = function(dataf, col1 = "column1", col2 = "column2") {
dataf$col1 = dataf$col2 # just as an example
}
The above, of course, does not work as intended. In some languages one
can force evaluation of a variable, and then
2000 Jan 06
1
nlme
Among others, datam contains the columns: logconc, tm, dose, subj, bilirubin.
None of these are factor variables.
The following compartment models work (the first still has not
converged after 100 interations):
res1 <- nlme(logconc~p2+p3+log(dose/(exp(p1)-exp(p2))*
(exp(-exp(p2)*tm)-exp(-exp(p1)*tm))),start=list(fixed=c(5,-2,-0.1)),
fixed=list(p1+p2+p3~1),control=list(maxIter=100),
2008 Dec 01
1
Help with lattice graphics
Hi,
I like the formatting and the appearance of lattice plots. But I have not succeeded in gettting the right format in my plots with the lattice package in one of my applications. In?the code shown below, I start by constructing a general data frame and show my attempts with the lattice package commands. After that, I use the graphics package and show the kind of plot that I want to get.
I would
2011 Mar 05
2
please help ! label selected data points in huge number of data points potentially as high as 50, 000 !
Dear All
I am reposting because I my problem is real issue and I have been working on
this. I know this might be simple to those who know it ! Anyway I need help
!
Let me clear my point. I have huge number of datapoints plotted using either
base plot function or xyplot in lattice (I have preference to use lattice).
name xvar p
1 M1 1 0.107983837
2 M2 11
2010 Aug 12
2
Append to csv without header
Hi,
I am writing a function that writes to a csv file for every call.
However, for the subsequent calls, I want to append the data to the existing
csv file without appending the column names again.
I tried searching in the previous posts, but I am stuck with different
errors.
Here is what I am doing (dataF is a data-frame):-
outputFilePath <- paste(getwd(), "/",
2004 Jun 24
3
The "median" function in R does not work properly.
Hi,
1.) The "median" function does not work well. Please refer to the data
below (same data is attached as txt-delimited). This is what I try to
do in R:
median ( dataf [2:9] )
I get warning: "needs numeric data"
2.) BUT if apply the median to a single vector:
median ( dataf [,2]] )
then it works:
3.) How come the "median"
2011 Mar 05
1
displaying label meeting condition (i.e. significant, i..e p value less than 005) in plot function
Dear R users,
Here is my problem:
# example data
name <- c(paste ("M", 1:1000, sep = ""))
xvar <- seq(1, 10000, 10)
set.seed(134)
p <- rnorm(1000, 0.15,0.05)
dataf <- data.frame(name,xvar, p)
plot (dataf$xvar,p)
abline(h=0.05)
# I can know which observation number is less than 0.05
which (dataf$p < 0.05)
[1] 12 20 80 269 272 338 366 368 397 403 432 453
2013 Jan 26
2
different legends in lattice panels
Hi listers,
I want to make lattice plots xyplots with the indication of legends
inside each panel with only the points and the lines actually ploted
inside each given panel according to the group(ing) factor.
The code below shows what I have achieved so far and I hope will make
clear what I want to have.
It seems to me that my solution is a very "dirty hack" and there
certainly is