Displaying 20 results from an estimated 2000 matches similar to: "I have a problem with the log2 function"
2003 May 28
2
how to get a line plot before/after treatment
Dear R help-list reader,
I would like to generate a plot which compares to states in a patient
treatment, before and after. for this reason I have generated a vector
before<-c(1,30,23,40)
and
after<-c(20,10,20,60)
the first element in "before" corresponds to the first element in "after".
I would like and generate a dotplot with
before and after as x-scale, the elements
2003 Aug 15
2
help with Tukey Mean-Difference Plot
Dear R users,
I would appreciate for some advise how to generate a Tukey
Mean-Difference Plot with the tmd function part of the lattice
library. I have two test results (log transformed) which showing a
correlation on a scatterplot. However the correlation line is
parallel displaced depending on a clinical condition. I thought to a
Tukey Mean Difference Plot would show me the difference
2003 May 26
1
help with subset(), still original dataframe in tapply
Dear R-help reader,
it would be great if someone knows what I'm doing wrong.
I have (shorten) dataframe, which consists of a group identification
and a number
>ex
UID REL
1 R1.B8.31 0.000
2 R1.B8.31 0.000
3 R1.B8.31 0.000
4 R1.B8.31 0.000
5 R1.B8.38 0.010
6 R1.B8.38 0.060
7 R1.B8.38 0.006
8 R1.B8.38 0.010
9 R1.B8.48 0.080
10 R1.B8.48 NA
11 R1.B8.48 0.006
I'm
2010 Mar 10
1
log2(quote(1:10)) evaluates the quoted 1:10, log() does not
This is very minor, but shouldn't log2(quote(1:10))
throw an error,the same as log() and other math functions
do? It looks like log2 and log10 evaluate a call object
instead of throwing a non-numeric-argument error. They
do object to non-call language objects, like expressions.
> log2(quote(1:10))
[1] 0.000000 1.000000 1.584963 2.000000 2.321928 2.584963
[7] 2.807355 3.000000
2003 Aug 22
1
advise for modeling a linear mixed model
Dear R help-list reader,
I'm trying to investigate my data with linear mixed model and are
seeking advise how to write the model in R. I was trying to get hold
of the recommended book from Bates et al, but neither the major
bookshop nor our university library had the book. My data is
mirroring the example given in the appendix of John Foxes book
"Applied Regression" with a
2003 May 28
2
? building a database with a the great examples
Dear R help reader,
I'm not an expert in R and are lerning a lot by reading the help
digest, which is sometimes difficult because the huge amount of data
posted. I have posted some questions before, and are impressed how
quick I got a solution for my problem. Sometimes with quite different
suggestions. I was always wondering if my questions didn't come up
before. On the other site,
2013 Nov 07
1
R interface to C API Rf_logspace_{add,sub}?
Is there an R-language interface to the R API C-language functions Rf_logspace_add()
and Rf_logspace_sub()? I don't see one but I may not looking under the
right name.
Various packages have functions which do that same sort
of thing (log(exp(x)+exp(y)) and log(exp(x)-exp(y)) without unnecessary
floating point errors). They have names like
matrixStats::logSumExp(lx, na.rm=FALSE, ...)
2008 Feb 27
1
Warnings generated by log2()/log10() are really large/takes a long time to display
x <- rnorm(1e6);
y <- log(x); # or logb(x) or log1p(x)
w <- warnings();
print(object.size(w));
## [1] 480
str(w);
$ NaNs produced: language log(x)
- attr(*, "dots")= list()
- attr(*, "class")= chr "warnings"
y <- log2(x); # or log10(x)
w <- warnings();
print(object.size(w));
## [1] 8000536
str(w);
## List of 1
## $ NaNs produced: language
2004 Nov 24
6
Searching for antilog function
Dear R-users,
I have a basic question about how to determine the antilog of a variable.
Say I have some number, x, which is a factor of 2 such that x = 2^y. I
want to figure out what y is, i.e. I am looking for the antilog base 2 of x.
I have found log2 in the Reference Manual. But I am struggling how to
get the antilog of that.
Any help will be appreciated!
> version
platform
2003 Jun 03
0
Rtips (was Re: ? building a database with a the great /cookbook
For me as a beginner a cookbook would be welcome. so many great code
examples are posted into the help list, but finding these is quite
difficult. I think it comes all down to the problem who is compiling
/ contributing and can judge what should go in.
In this respect, Detlef Steuer (suggestion , might be a solution
http://fawn.unibw-hamburg.de/cgi-bin/Rwiki.pl?RwikiHome.
Frank
>
2017 Feb 17
4
Wish List: Extensions to the derivatives table
The derivative table resides in the function D. In S+ that table is extensible because it is written in the S language. R is faster but less flexible, since that table is programmed in C. It would be useful if R provided a mechanism for extending the derivative table, or barring that, provided a broader table. Currently unsupported mathematical functions of one argument include expm1, log1p,
2005 Oct 31
3
question about precision, floor, and powers of two.
At the risk of being beaten about the face and body, can somebody explain
why the middle example: log2(2^3); floor(log2(2^3)) is different than
examples 1 and 3?
> log2(2^2); floor(log2(2^2))
[1] 2
[1] 2
> log2(2^3); floor(log2(2^3))
[1] 3
[1] 2
> log2(2^4); floor(log2(2^4))
[1] 4
[1] 4
>
DrC
[[alternative HTML version deleted]]
2006 May 17
1
for loops and counter interpolation
Hi
I'm sorry about the triviality of my problem. I have a vector (v) of three
columns (logA, logB, id). I want to compute (and plot) the correlation between
logA and logB for different thresholds of id (e.g. >30, etc). So I tried:
for(i in 1:100){
points(cor(v$logA[v$id>i], v$logB[v$id>i], use="complete.obs"), i))
}
(i created a plot object already)
but it comes with
2017 Feb 17
1
Wish List: Extensions to the derivatives table
The issue is that without an extensible derivative table or the proposed extensions, it is not possible to automatically produce (without manual modification of the deriv3 output) a function that avoids catastrophic cancellation regardless of the working range.
Manual modification is not onerous as a one-time exercise, but can be time consuming when it must be done numerous times, for example
2018 Feb 06
2
libc++ cross-compile linux-armv7 and math function problems
Hello,
I am trying to cross-compile libc++ from my x86_64 linux system to armv7hf.
We have our own gcc compiler that we build with crosstools-ng (based on gcc
6.3.0) and I set my environment like this:
CC=armv7a-plex-linux-gnueabihf-gcc
CXX=armv7a-plex-linux-gnueabihf-g++
CFLAGS=-fPIC -DPIC -mfloat-abi=hard -march=armv7-a -Os -mfpu=vfpv3-d16
--sysroot=<path>
CXXFLAGS=-fPIC -DPIC
2005 Feb 02
3
publishing random effects from lme
Dear all,
Suppose I have a linear mixed-effects model (from the package nlme) with
nested random effects (see below); how would I present the results from
the random effects part in a publication?
Specifically, I?d like to know:
(1) What is the total variance of the random effects at each level?
(2) How can I test the significance of the variance components?
(3) Is there something like an
2011 Jun 13
2
log2() and -min() very quick question
I'm looking over good-code a post-doc in my lab wrote and trying to learn
how it works. I came across the following:
rel.abundance <- as.matrix(read.delim("rel.abundance.csv",row.names=1,as.is
=TRUE))
rel.abundance <- log2(rel.abundance-min(rel.abundance)+1)
I'm not sure what the second line is doing. I ran each line in R and
couldn't see a noticeable difference in
2003 Jan 24
1
different plot symbols according to a factor
Dear R list subscriber,
I'm hoppiing my question didn't come up so far. I try to do somthing simple
a<-c(1,4,5,2,7,34,56,78,76,54)
b=c(a<-c(1,4,5,2,7,34,56,78,76,54)
c<-c(0,0,0,0,0,1,1,1,1,1)
I would like to get a scatter diagram with different plot symbol for 0 and
1 in c
I tried
plot(a,b, pch=c(1,2)[c])
which didn't work.
I appreciate if someone from the list could
2001 Nov 23
3
compiling R under hpux
Dear R user,
I'm wondering if anyone was succesful in compiling R under hpux 10.20
I couldn't compile verion 1.2.1 or 1.3.
I asked this question two weeks ago, but nobody replyed. Looks that not
many people are using hpux machines.
Thanks
Frank Mattes
Department of Virology
Royal Free Hospital
London
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r-help
2002 Mar 06
3
help with combining data frames
Dear R user,
I'm relative new and need some help / advise from you. I have
organised my data in several frames, mainly because the data came
from different sources. One common variable in all data frames is the
day post transplantation. I would like to combine the data frame to
one big data frame which contains all the data, however no duplicate
rows should occour (only one row for one