Displaying 20 results from an estimated 900 matches similar to: "R and QSAR equations"
2007 Aug 30
1
categorical variable coefficients in QSAR
Dear list:
I am interested in the following sort of problem, as is found frequently
in the field of QSAR. I have biological activity as a function of chemical
structure, with structure defined in a categorical manner in that the
SUBSTITUENT is the levels of the POSITION factor. For example, data from
Kubinyi (http://www.kubinyi.de/dd-12.pdf) for this type of analysis is
presented as follows:
2010 Mar 06
3
scientific (statistical) foundation for Y-RANDOMIZATION in regression analysis
Dear all,
I am a statistician doing research in QSAR, building regression models where the dependent variable is a numerical expression of some chemical activity and input variables are chemical descriptors, e.g. molecular weight, number of carbon atoms, etc.
I am building regression models and I am confronted with a widely a technique called Y-RANDOMIZATION for which I have difficulties in
2007 Aug 30
5
Single plot multiple levels in x?
Plotting with 2 x axis?
One axis inside another, for example salary within state,
1-50 | 50 ? 100 | 100+ | 1- 50 | 50 -100 | 100+ | ? repeated bins for salary
AL ! AR ?? more states
The values are all stored with a single data frame. I have tried different things with the axis function and done many
2012 Mar 08
2
Regarding randomForest regression
Sir,
This query is related to randomForest regression using R.
I have a dataset called qsar.arff which I use as my training set and
then I run the following function -
rf=randomForest(x=train,y=trainy,xtest=train,ytest=trainy,ntree=500)
where train is a matrix of predictors without the column to be
predicted(the target column), trainy is the target column.I feed the same
data
2008 Nov 01
2
antispam plugin problem
Hi people!
(Especially Johannes, probably =)
I recently switched to DSPAM + antispam plugin combination.
Mostly I am happy but there is a problem with calling dspam-exec in order to
relearn the messages.
Moving messages to spam folder does not work, giving the error message
'Failed to call dspam' to client.
I tried to add some debug output and here are the results:
This is the output of
2010 Jul 07
2
how to define method for "+" function in a new class
Dear R developers,
I have a new class, which I called "Molecule", and have tried to define =
a "+" operation for 2 objects of this class.
This is what I have written so far, although the method is not complete =
(I'm trying to look at it at intermediate stages):
setMethod(
f=3D"+",
signature(x=3D"Molecule",y=3D"Molecule"),
2011 May 19
3
A better way to do this
Hello gurus,
I have a dataframe containing two groups viz., 'control' and 'case', each of
these groups contains longitudinal data for 100 subjects. I have to plot all
these subjects on a single chart and then put a regression line for each of
the group for all the subjects. I have written a function to do the chart
grpcharts<-function (dat, group,group2,molecule,cutoff){
2011 Apr 29
6
Bigining with a Program of SVR
Hi:
I'm starting a research of Support Vector Regression. I want to obtain a
model to predict a property A with
a set of property B, C, D, ... This problem is very common for example in
QSAR models. I want to know
some examples and package that could help me in this way. I know about
caret and e1071. But I' don't
know if this package can work with continues variables.?
2012 Jan 30
1
Need to Write a Code that can find the molecular weight of various compounds
Hi!
Just started working at a lab and have only minimal experience with R.
I was wondering if there was a way to write a code that would intake a data
set of chemical compounds (ex: H2O, CH3)
and be able to give an output column of the molecular weight?
I tried some really basic coding to try to work with a being a matrix of
data with the assigned variables.
if (A<-'H')
2003 Jan 14
3
PLS regression?
Hi all,
I would like to do some QSAR analysis (quantitative structure activity
relationship). I need to use some Partial Least Squares (PLS) regression,
but I have not seen this option on the R-project. Is it possible to do this
kind of regression on R?
thank you in advance
best regards,
olivier
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2011 Nov 30
1
Invalid number of components, ncomp
Error in mvr(Kd_nM ~ qsar, ncomp = 6, data = my, validation = "CV", method = "kernelpls") :
Invalid number of components, ncomp
How I can fix this?
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2010 Mar 01
0
Is package "dr" appropriate for reducing the dimensionality of molecules conformational space ?
I anticipate lacking of prior experience with dimensionality reduction problems.
Some scientists concerned with drug discovery performed several steered Molecular Dynamics simulations of the
alanine-dipeptide molecule dragged by a radial force from an equilibrium conformation to another different equilibrium conformation.
They sampled at regular intervals 7 dihedral angles, 5 bending angles, and
2004 Feb 23
1
Reference to use of MLR in industry and biology
I apologize in advance for posting a question not related to R.
I need references to papers that use multiple linear regression in an industrial application and also in a biological experiment.
This is aimed to biologists/chemists (non-statisticans) so if anyone has written a brilliant paper where the use of multiple regression is important and also understandable to people with little
2005 Oct 10
1
text(x,y,greek character)
Dear list,
I would like to plot points with two types of labels, one at the data
point (the name of the point) and another offset a bit with another
factor which is either of the two greek characters alpha or beta. I have
tried to get the routine to plot a greek character with expression() or
with substitute() and have not yet had any success. The following only
plots the word in english in
2012 Sep 14
0
rcdk package, fingerprint without name?
Hi!
I have a question concerning the rcdk package:
I generated a test sdf-file with 3 molecules in it and tried to perform clustering by fingerprints and plot the results in a dendogramm.
This is what I did:
mols <- load.molecules ("molecules.sdf")
fp.list <- lapply (mols, get.fingerprint, 'maccs')
fp.dist <- fp.sim.matrix (fp.list, method='tanimoto')
2022 Nov 16
2
Trouble with kernel-3.10.0-1160.80.1.el7.x86_64
>
> On 2022-11-08 15:49, Orion Poplawski wrote:
>
> On 11/8/22 13:12, Simon Matter wrote:
>
> Is anyone else experiencing trouble with
> kernel-3.10.0-1160.80.1.el7.x86_64?
>
> I'm seeing a kernel panics in the kvm module on one of our VM hosts with
>
> it.
>
> I did notice a new libvirt
2005 Aug 10
3
Hitachi wip5000
Hi all,
Saw on the net the wip5000 SIP wireless phone from Hitachi, a suprising rig.
As anyone successfull in making it work with Asterisk?
If so, how do you like it?
Regards,
Francois
Random Thought:
---------------
Molecule, n.:
The ultimate, indivisible unit of matter. It is distinguished
from the corpuscle, also the ultimate, indivisible unit of matter, by a
closer resemblance to
2012 Oct 05
5
IPv6 & SSL
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi,
I have a dual stack server with Dovecot 2.1.10 listening on v4 and v6
Dovecot has a Comodo SSL certificate issued via NameCheap that works as
expected with IPv4
in 10-ssl.conf I have enabled these configuraction directives:
ssl = yes
ssl_cert = < /path/to/file.crt
ssl_key = < /path/to/file.key
ssl_parameters_regenerate = 202 hours
If I
2009 Sep 09
2
ggplot2: mixing colour and linetype in geom_line
Hi all,
I try to represent a multiple curve graphic where the x-axis is the
temperature and the different y-axes are the different X (X22,X43,X44...)
some X corresponds to the same molecule (22 and 44 are for CO2 for instance)
so I use the same colour for them.
I wanna mix the linetype with the colour to be able to visually see the
difference between X43 and X45
The best I have done up to now
2006 Dec 20
3
How to use strings from a data.frame as the argument of an expression() for plot
Greetings,
I would like to use a data.frame with strings to feed
the expression() in the title of a plot. The way I did
this is:
molecules
<-data.frame(name=c("o3","no","no2"),expression=c("quote(O[3])","quote(NO)","quote(NO[2])"))
for (mol in c(5,7,9)) {
plot(x, y, type="b",