RE: [R] postscript/eps label clipping

2003-07-11 Thread Mulholland, Tom
I guess I was wrong there. However it does seem that it will come down
to fontsize 9 without clipping (or if it does I find it hard to see).

-Original Message-
From: Mulholland, Tom 
Sent: Friday, 11 July 2003 1:38 PM
To: David Forrest; [EMAIL PROTECTED]
Subject: RE: [R] postscript/eps label clipping


Never having used postscript as an output method I looked to see what
you were talking about. I  noted that ps.options needs to be called
before calling postscript. ps.options does have pointsize within it and
silly though it may seem, its what I would do next.

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[R] Sections for help files

2003-07-11 Thread Rob Hyndman
When compiling a package, is there any way of making the help files
(html or chtml) have separate sections for functions and data sets? When
looking at the help file for a package with a large number of help
pages, it would be nice to have the functions appear first and the data
sets appear second rather than have them jumbled together
alphabetically.

Currently, under Windows, chtml files have an tree index with object
names under one node and object Titles under another node. Something
like this would work with one node for functions and one node for data
sets. 

Can this be done? Would it be possible to incorporate such a feature
into future releases, either optionally or as the standard for all
packages?

Rob Hyndman 
___
Rob J Hyndman
Associate Professor  Director of Consulting
Department of Econometrics  Business Statistics
Monash University, VIC 3800, Australia.
http://www-personal.buseco.monash.edu.au/~hyndman/

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[R] info

2003-07-11 Thread Andrea Calandra
HI

I'm a student in chemical engineering, and i have to implement an algoritm about FIVE 
PARAMETERS INTERPOLATION for a calibration curve (dose, optical density)

y = a + (c - a) /(1+ e[-b(x-m])

where
x = ln(analyte dose + 1)
y = the optical absorbance data
a = the curves top asymptote
b = the slope of the curve
c = the curves bottom asymptote
m = the curve X intercept

Have you never seen this formula, because i don't fine information or
lecterature about solution of this!!!

Can i help me

Hi 
Mr. Calandra

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Re: [R] Exporting data

2003-07-11 Thread Jonathan Baron
On 07/11/03 09:58, C.E.Marshall wrote:
I am running simulations calculating correlation coefficients from bivariate 
data and I was wondering whether there is a way of exporting 1000 simulation 
results from R to a text file or to another file for further manipulation. I 
am having difficulty I think because of the text combined in with the 
numerical results.

If I understand you, it would seem that the trick is to put the
results of your simulation into a matrix or data frame, possibly
with one row or column per result.  I assume that each result
consists of a few numbers, each representing some variable.  Then
use write.table, write.matrix, or write.

-- 
Jonathan Baron, Professor of Psychology, University of Pennsylvania
Home page:http://www.sas.upenn.edu/~baron
R page:   http://finzi.psych.upenn.edu/

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Re: [R] info

2003-07-11 Thread Spencer Graves
I assume you mean the following:

chemYield -
function(a, x)(a[1]+(a[3]-a[2])/(1+exp(-a[2]*(x-a[4]))
	  If you want to estimate parameters a[1:4] from data on pairs of (x, 
y=chemYield), create a data.frame(x, y), and estimate the parameter 
vector a using nls.

	  If you have trouble getting nls to converge, I would plot the data 
and make a serious effort to get good starting values for a from the 
plot.  If I still have trouble, I'd try optim, then feed the output 
from optim into nls.

	  I seem to recall having seen problems like this discussed in Bates 
and Watts (1988) Nonlinear Regression Analysis and Its Applications 
(Wiley).  I don't have the book in hand at the moment, so I can't give 
you a page reference, but they discuss problems of this nature.  Bates 
was a pioneer in developing measures of intrinsic vs. parameter effects 
curvature.  Bates and Watts studied many published data sets and found 
that in nearly all cases, the parameter effects curvature was at least 
an order of magnitude larger than the intrinsic curvature.  That means 
that numerical difficulties can often (usually?) be improved by trying 
different parameterizations for the same problem.

	  The function nls and similar functions are described among other 
places in Venables and Ripley (2002) Modern Applied Statistics with S, 
4th ed. (Springer, ch. 8).

hope this helps.  spencer graves

Andrea Calandra wrote:
HI

I'm a student in chemical engineering, and i have 
to implement an algoritm about FIVE PARAMETERS
INTERPOLATION for a calibration curve (dose, optical density)
y = a + (c - a) /(1+ e[-b(x-m])

where
x = ln(analyte dose + 1)
y = the optical absorbance data
a = the curves top asymptote
b = the slope of the curve
c = the curves bottom asymptote
m = the curve X intercept
Have you never seen this formula, because i don't fine information or
lecterature about solution of this!!!
Can i help me

Hi 
Mr. Calandra

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[R] unz()

2003-07-11 Thread Marsland, John

I am having problems getting the unz() function to work as a connection to
start reading a file...

z - unz(c:/temp/stoxx.zip, close_tmi_components.txt, r)
readLines(z,2)

yields the following problems:

 z - unz(c:/temp/stoxx.zip, close_tmi_components.txt, r)
Error in unz(c:/temp/stoxx.zip, close_tmi_components.txt, r) : 
unable to open connection
In addition: Warning message: 
cannot locate file `close_tmi_components.txt' in zip file
`c:/temp/stoxx.zip' 
 readLines(z,2)
Error in readLines(z, 2) : cannot open the connection
In addition: Warning message: 
cannot locate file `close_tmi_components.txt' in zip file
`c:/temp/stoxx.zip' 

can anybody offer any advice?

Regards,

John Marsland


** 
This is a commercial communication from Commerzbank AG.\ \ T...{{dropped}}

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[R] unimodality test

2003-07-11 Thread Jerome Sackur
Dear R users,

I am interested in uni- bi- multimodality tests, for analysing reaction
times data. I was lead to Hartigan's dip test (Ann. Statistics, 13, 1985,
pp. 70-84, Applied Statistics, 34, 1985, 320-325). Not being a programmer
I am unable to translate the Fortran code given in ref. 2 into a R
function. I'd be glad to learn that someone already did it, or has devised
a better solution for this kind of problem..



Thanks a lot in advance,

J. Sackur
Inserm U562
Orsay, France

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[R] short puzzles

2003-07-11 Thread Marc Vandemeulebroecke
Dear R users,

can someone help with these short puzzles?

1) Is there a function like outer() that evaluates a three-argument function
on a threedimensional grid - or else how to define such a function, say,
outer.3()? E.g., calculate (x/y)^z on (x,y,z) element of {1,2,3}x{3,4}x{4,5} and
return the results in a 3-dimensional array. I would naively use outer() on
two of the arguments within a for() loop for the third argument and somehow
glue the array together. Is there a better way? What about outer.4(), or even
outer.n(), generalizing outer() to functions with an arbitrary number of
arguments?

2)
Define a function dimnames.outer() such that dimnames.outer(x, y, *)
returns, for x - 1:2, y - 2:3, the following matrix:

   y
x   2 3
  1 2 3
  2 4 6

(Or does such such a function already exist?)

3)

How to combine puzzle 1 and puzzle 2? A function dimnames.outer.n() would be
a nice little tool.

4)

How can I access, within a function, the name of a variable that I have
passed to the function? E.g., letting a - 2, and subsequently calling function
f(a) as defined below,

f - function (x) {
  # How can I get a out of x?
}

5)

Finally: Letting x - 2, how can I transform x+y into 2+y (as some
suitable object), or generally func(x,y) into func(2,y)?

Many thanks,
Marc

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Re: [R] FITS File Reader

2003-07-11 Thread Duncan Murdoch
On Thu, 10 Jul 2003 19:09:16 -0700 (PDT), Nicholas Konidaris
[EMAIL PROTECTED] wrote :

Dear R users,

   I have searched the web and CRAN fairly carefully.  Does a FITS
format file reader for R currently exist that I can download?

www.wotsit.org has a 13 year old document describing FITS, which seems
to be a fairly open-ended format,  so it may not cover what you need.
However, it looks reasonably straightforward to read it using the
stream functions:  look at the help topics ?file, ?readLines, and
?readBin.

If you do locate code to read it, or you end up writing some yourself,
you should consider contributing it to the foreign package.

Duncan Murdoch

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Re: [R] short puzzles

2003-07-11 Thread Sundar Dorai-Raj


Marc Vandemeulebroecke wrote:
Dear R users,

can someone help with these short puzzles?

1) Is there a function like outer() that evaluates a three-argument function
on a threedimensional grid - or else how to define such a function, say,
outer.3()? E.g., calculate (x/y)^z on (x,y,z) element of {1,2,3}x{3,4}x{4,5} and
return the results in a 3-dimensional array. I would naively use outer() on
two of the arguments within a for() loop for the third argument and somehow
glue the array together. Is there a better way? What about outer.4(), or even
outer.n(), generalizing outer() to functions with an arbitrary number of
arguments?
2)
Define a function dimnames.outer() such that dimnames.outer(x, y, *)
returns, for x - 1:2, y - 2:3, the following matrix:
   y
x   2 3
  1 2 3
  2 4 6
(Or does such such a function already exist?)

3)

How to combine puzzle 1 and puzzle 2? A function dimnames.outer.n() would be
a nice little tool.
Here's what I came up with. If you need the other functions you 
mentioned, you can extract them from this example.

outer.3 - function(x, y, z, FUN, ...) {
  print(deparse(substitute(x))) # for question 2
  n.x - NROW(x)
  n.y - NROW(y)
  n.z - NROW(z)
  nm.x - if(is.array(x)) dimnames(x)[[1]] else names(x)
  nm.y - if(is.array(y)) dimnames(y)[[1]] else names(y)
  nm.z - if(is.array(z)) dimnames(z)[[1]] else names(z)
  X - expand.grid(x = x, y = y, z = z)
  f - FUN(X$x, X$y, X$z, ...)
  array(f, dim = c(n.x, n.y, n.z),
dimnames = list(nm.x, nm.y, nm.z))
}
a - 1:3
b - 3:4
c - 4:5
names(a) - a
names(b) - b
names(c) - c
outer.3(a, b, c, function(x, y, z) (x/y)^z)
outer.3(as.matrix(a), as.matrix(b), as.matrix(c),
function(x, y, z) (x/y)^z)
4)

How can I access, within a function, the name of a variable that I have
passed to the function? E.g., letting a - 2, and subsequently calling function
f(a) as defined below,
f - function (x) {
  # How can I get a out of x?
}
Use deparse(substitute(x)). See example above.

5)

Finally: Letting x - 2, how can I transform x+y into 2+y (as some
suitable object), or generally func(x,y) into func(2,y)?
Use substitute(func(x, y), list(x = 2)).

Hope this is useful,

Sundar

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Re: [R] FITS File Reader

2003-07-11 Thread Barry Rowlingson
Duncan Murdoch wrote:

If you do locate code to read it, or you end up writing some yourself,
you should consider contributing it to the foreign package.
There's a C (and fortran)-level library for reading FITS files here:

http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html

 - together with addons for Perl, Python, C++ etc. Coding an R 
interface would be a nice exercise in R coding.

 I would have already written this if not for the fact that most of the 
high-dimensional data that I deal with gets written with some awful 
unformatted fortran IO rubbish that needs reverse-engineering and 
byte-swapping. Haven't these people heard of HDF or FITS?? *sigh*

 Also, I notice that SciLab can read FITS files, by using ImageMagick, 
which can read FITS files ImageMagick could convert it to something 
readable by R, I guess This would be the dirty hack solution.

Baz

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Re: [R] Nonliner Rgression using Neural Nnetworks

2003-07-11 Thread Frank E Harrell Jr
On Fri, 11 Jul 2003 18:56:58 +0900
Yukihiro Ishii [EMAIL PROTECTED] wrote:

 Hi, 
 I am an old hand at chemistry but a complete beginner at statistics
  including R computations.
 My question is whether you can carry out nonlinear
 multivariate regression  analysis in  R using neural networks, where the
 output variable can range from -Inf to  + Inf., unlike discriminant 
 analysis where the output is confined to one  or zero. The library nnet
 seems to work only in the latter case but then I could  be wrong. 
 
 Please help me there.
 
 Thanks in advance.
 
 Y.Ishii [EMAIL PROTECTED]
 257-0002 Japan

You might want to look at the paper at

http://brain.cs.unr.edu/publications/goodman.ann_advantages.jasa99.pdf

The work was done using a nice standalone neural net program Nevprop by Goodman and 
colleagues, which is intended for binary outcomes and incorporates bootstrapping for 
estimating predictive accuracy of the network.

You may obtain Nevprop at http://brain.cs.unr.edu
---
Frank E Harrell Jr  Prof. of Biostatistics  Statistics
Div. of Biostatistics  Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat

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RE: [R] info

2003-07-11 Thread Paul, David A
The most commonly used dose-response functions for nonlinear calibration 
curves are the four- and five-parameter logistic functions.  The four-
parameter logistic is specified as

F(z) = delta + (alpha - delta)/(1 + (z/gamma)^beta)

so I'm not sure where you are getting your dose-response functional form
from.  In any case, you can fit this model using either nls( ) or nlme( ),
depending on whether or not you want to fit a random-effects model.
For references related to the four- and five-parameter logistic functions,
you can read

1.  Rodbard, D., and Frazier, G.R. (1975) Statistical analysis of
radioligand
assay data, Methods Enzymol., vol. 37, p. 3 - 22.

2.  Dudley, R.A., Edwards, P., and Ekins, R.P.  (1985)  Guidelines for 
immunoassay data processing, Clin. Chem., vol. 31, no. 8, p. 1264 - 1271

The first of these articles introduces the four-parameter logistic, and the
second refines its parametrization as well as introduces the five-parameter
logistic for use in situations where the calibration curve is asymmetric.
You should also acquire Mixed Effects Models in S and Splus, by Drs.
Pinheiro and Bates if you intend to do anything with mixed effects models.


Best,
 
 david paul



-Original Message-
From: Andrea Calandra [mailto:[EMAIL PROTECTED] 
Sent: Thursday, July 10, 2003 11:39 AM
To: [EMAIL PROTECTED]
Subject: [R] info


HI

I'm a student in chemical engineering, and i have to implement an algoritm 
about FIVE PARAMETERS INTERPOLATION for a calibration curve (dose, optical
density)

y = a + (c - a) /(1+ e[-b(x-m])

where
x = ln(analyte dose + 1)
y = the optical absorbance data
a = the curves top asymptote
b = the slope of the curve
c = the curves bottom asymptote
m = the curve X intercept

Have you never seen this formula, because i don't fine information or 
lecterature about solution of this!!!

Can i help me

Hi 
Mr. Calandra

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[R] correlation, import of large tables,test for point-biserial c.c.?

2003-07-11 Thread ArneSaatkamp
Dear R help community,

I want to calculate correlations between environment parameters and species
abundance data. When I use the cor() for my table (121 columns 91 rows) R
generates a dataset with the correlations between all columns; 

1) How can I limit the calculations to the correlations of only the first
column with every other ? (Or:) How can I extract the line/row in question from
the cor() dataset produced by R ?

2) I assume that with one continuous factor and the other binary (0/1), 
cor() gives the point-biserial correlation coefficient, but how can I find the
method used by R ?

3) I was not able to import (from Excel) the whole 121x67 table, for
instance I divided it into pieces. Is there a simple solution to import the whole
file ?

4) In the end I want to test the correlation coefficients. Where do I find
an appropriated test for the point biserial correlation ? Can R calculate the
coefficient and test it for all data in one step ?

I just started working  learning with R, but even after reading the R-help
and Introduction to R, I still have big difficulties, so
Thanks in advance for your help !!

Arne Saatkamp

Arne Saatkamp
Inst. f. Biol. II - Abt. f. Geobotanik
Schänzlestr. 1
79104 Freiburg
Germany

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Re: [R] unimodality test

2003-07-11 Thread Martin Maechler
 Jerome == Jerome Sackur [EMAIL PROTECTED]
 on Fri, 11 Jul 2003 12:17:33 +0200 (MET DST) writes:

Jerome Dear R users, I am interested in uni- bi-
Jerome multimodality tests, for analysing reaction times
Jerome data. I was lead to Hartigan's dip test
Jerome (Ann. Statistics, 13, 1985, pp. 70-84, Applied
Jerome Statistics, 34, 1985, 320-325). Not being a
Jerome programmer I am unable to translate the Fortran code
Jerome given in ref. 2 into a R function. I'd be glad to
Jerome learn that someone already did it, or has devised a
Jerome better solution for this kind of problem..

I had got a version with Fortran and S-plus from Dario Ringach
(@ NYU.edu) in 1994 (from what I see) and had worked on it in 2000,
made it into an R package back then.
The reason it hasn't made its way to CRAN was that the Fortran code
(which I f2c'ed to C) still has bugs (leading to segmentation
faults)  that I've not yet found time to debug.

Let me have a look at it before making it available (not on
CRAN) but via FTP as a source package.

Martin Maechler [EMAIL PROTECTED] http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum  LEO C16Leonhardstr. 27
ETH (Federal Inst. Technology)  8092 Zurich SWITZERLAND
phone: x-41-1-632-3408  fax: ...-1228   

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[R] hazard estimate

2003-07-11 Thread Dr. Peter Schlattmann
Dear list,

is there a function available which provides an estimate of the hazard
function
based on a cox proportional hazard model? I only found the cumulative
hazard and the survival function as survfit options.

Thanks for your help
Peter

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RE: [R] Exporting data

2003-07-11 Thread Adaikalavan Ramasamy
This really depends on what your output is. As previously suggested
save() and write() are excellent suggestions.

for(ii in 1:1000){
out - cor( x[ii, ], y[ii, ] ) # or whatever 
cat(ii, \t, out, \n, append=TRUE, file=output.txt)
}

This method is really not worth it for small simulations but I found
this to be extremely useful with large simulations. 

The output file can act both as log/progress report file and provide
partial results even if your program crashes. More sophisticated method
can be found under connections().


-Original Message-
From: C.E.Marshall [mailto:[EMAIL PROTECTED] 
Sent: Friday, July 11, 2003 4:59 PM
To: [EMAIL PROTECTED]
Subject: [R] Exporting data


Dear All

I am a new user to R and so I have a question which I hope you can help
me 
with.

I am running simulations calculating correlation coefficients from
bivariate 
data and I was wondering whether there is a way of exporting 1000
simulation 
results from R to a text file or to another file for further
manipulation. I 
am having difficulty I think because of the text combined in with the 
numerical results.

Many Thanks

Carolyn Marshall

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[R] Offsets in glmmPQL?

2003-07-11 Thread Anon.
I've got a colleague who's using a GLMM to analyse her data, and I've 
told her that she needs to include an offset.  However, glmmPQL doesn't 
seem to allow one to be included.  Is there anyway of doing this?

Bob

--
Bob O'Hara
Rolf Nevanlinna Institute
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
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Re: [R] info

2003-07-11 Thread Spencer Graves
	  Calandra's dose-response function is very close to what you wrote: 
She has x = ln(z+1), while x = ln(z) and m = ln(gamma) would give what 
you wrote.  I would guess that your comments and references should help 
her.

Spencer Graves	

Paul, David A wrote:
The most commonly used dose-response functions for nonlinear calibration 
curves are the four- and five-parameter logistic functions.  The four-
parameter logistic is specified as

F(z) = delta + (alpha - delta)/(1 + (z/gamma)^beta)

so I'm not sure where you are getting your dose-response functional form
from.  In any case, you can fit this model using either nls( ) or nlme( ),
depending on whether or not you want to fit a random-effects model.
For references related to the four- and five-parameter logistic functions,
you can read
1.  Rodbard, D., and Frazier, G.R. (1975) Statistical analysis of
radioligand
assay data, Methods Enzymol., vol. 37, p. 3 - 22.
2.  Dudley, R.A., Edwards, P., and Ekins, R.P.  (1985)  Guidelines for 
immunoassay data processing, Clin. Chem., vol. 31, no. 8, p. 1264 - 1271

The first of these articles introduces the four-parameter logistic, and the
second refines its parametrization as well as introduces the five-parameter
logistic for use in situations where the calibration curve is asymmetric.
You should also acquire Mixed Effects Models in S and Splus, by Drs.
Pinheiro and Bates if you intend to do anything with mixed effects models.
Best,
 
 david paul



-Original Message-
From: Andrea Calandra [mailto:[EMAIL PROTECTED] 
Sent: Thursday, July 10, 2003 11:39 AM
To: [EMAIL PROTECTED]
Subject: [R] info

HI

I'm a student in chemical engineering, and i have to implement an algoritm 
about FIVE PARAMETERS INTERPOLATION for a calibration curve (dose, optical
density)

y = a + (c - a) /(1+ e[-b(x-m])

where
x = ln(analyte dose + 1)
y = the optical absorbance data
a = the curves top asymptote
b = the slope of the curve
c = the curves bottom asymptote
m = the curve X intercept
Have you never seen this formula, because i don't fine information or 
lecterature about solution of this!!!

Can i help me

Hi 
Mr. Calandra

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Re: [R] hazard estimate

2003-07-11 Thread Spencer Graves
	  The hazard function is the derivative of the cumulate hazard.  There 
was a discussion only a few days ago on smoothing the hazard rate, which 
as I recall may have dealt with smoothing the cumulative hazard and then 
differentiating that.

	  Have you checked http://www.r-project.org/ - search - R site 
search?  I just got 24 hits for smooth hazard.  If you don't get the 
answer from someone else here and an R site search does not produce what 
you want, then try r-help again.

hope this helps.  spencer graves

Dr. Peter Schlattmann wrote:
Dear list,

is there a function available which provides an estimate of the hazard
function
based on a cox proportional hazard model? I only found the cumulative
hazard and the survival function as survfit options.
Thanks for your help
Peter
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Re: [R] correlation, import of large tables, test for point-biserialc.c.?

2003-07-11 Thread Spencer Graves
Did you look at ?cor?

The documentation observes that cor accepts an optional second argument. 
 The following works:
 df1 - data.frame(a=1:8, b=rep(c(-1, 1), 4),
+  c=rep(c(-1, 1), each=4))
 cor(df1[,1], df1[, -1])
 b c
[1,] 0.2182179 0.8728716

hope this helps.  spencer graves

[EMAIL PROTECTED] wrote:
Dear R help community,

I want to calculate correlations between environment parameters and species
abundance data. When I use the cor() for my table (121 columns 91 rows) R
generates a dataset with the correlations between all columns; 

1) How can I limit the calculations to the correlations of only the first
column with every other ? (Or:) How can I extract the line/row in question from
the cor() dataset produced by R ?
2) I assume that with one continuous factor and the other binary (0/1), 
cor() gives the point-biserial correlation coefficient, but how can I find the
method used by R ?

3) I was not able to import (from Excel) the whole 121x67 table, for
instance I divided it into pieces. Is there a simple solution to import the whole
file ?
4) In the end I want to test the correlation coefficients. Where do I find
an appropriated test for the point biserial correlation ? Can R calculate the
coefficient and test it for all data in one step ?
I just started working  learning with R, but even after reading the R-help
and Introduction to R, I still have big difficulties, so
Thanks in advance for your help !!
Arne Saatkamp

Arne Saatkamp
Inst. f. Biol. II - Abt. f. Geobotanik
Schänzlestr. 1
79104 Freiburg
Germany
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RE: [R] correlation, import of large tables,test for point-biserial c.c.?

2003-07-11 Thread Adaikalavan Ramasamy
1) Calculating a 121 x 121 correlation matrix and then extracting the relevant 
correlating is extremely inefficient and slow. Instead try this :

data  - as.matrix( data )   # data is your 91 x 121 matrix or 
dataframe
colInterest   - data[ ,1]
apply( data, 2, function(x) cor(x , colInterest) )


Here you take each column of data (at which point it becomes a vector called x) and 
calculates its correlation. apply() is an efficient form of for() loop.


3) I have imported files of much bigger dimensions without any problem. First of all 
ensure that the data is in tab delimited or comma seperated not .xls. Next use 
read.delim or read.csv to read in the file. 

If the file is only partially loaded or garbled up, then check for special characters. 
Most often the culprit is the comment character #. Sometimes % @ etc can also cause a 
problem. 

I have no idea about the other questions. If you type in help.start(), you will get a 
help page where you can do a keyword search etc.


-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 
Sent: Friday, July 11, 2003 10:01 PM
To: [EMAIL PROTECTED]
Subject: [R] correlation, import of large tables,test for point-biserial c.c.?


Dear R help community,

I want to calculate correlations between environment parameters and species abundance 
data. When I use the cor() for my table (121 columns 91 rows) R generates a dataset 
with the correlations between all columns; 

1) How can I limit the calculations to the correlations of only the first column with 
every other ? (Or:) How can I extract the line/row in question from the cor() dataset 
produced by R ?

2) I assume that with one continuous factor and the other binary (0/1), 
cor() gives the point-biserial correlation coefficient, but how can I find the method 
used by R ?

3) I was not able to import (from Excel) the whole 121x67 table, for instance I 
divided it into pieces. Is there a simple solution to import the whole file ?

4) In the end I want to test the correlation coefficients. Where do I find an 
appropriated test for the point biserial correlation ? Can R calculate the coefficient 
and test it for all data in one step ?

I just started working  learning with R, but even after reading the R-help and 
Introduction to R, I still have big difficulties, so Thanks in advance for your help !!

Arne Saatkamp

Arne Saatkamp
Inst. f. Biol. II - Abt. f. Geobotanik
Schänzlestr. 1
79104 Freiburg
Germany

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Re: [R] hazard estimate

2003-07-11 Thread Ruud H. Koning
library(survival)
?basehaz

gives

  For `basehaz', a dataframe with the baseline hazard, times, and
 strata.


Ruud 

*** REPLY SEPARATOR  ***

On 7/11/2003 at 4:01  Dr. Peter Schlattmann wrote:

Dear list,

is there a function available which provides an estimate of the hazard
function
based on a cox proportional hazard model? I only found the cumulative
hazard and the survival function as survfit options.

Thanks for your help
Peter

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Thanks: [R] short puzzles

2003-07-11 Thread Marc Vandemeulebroecke
Thanks to Andy Liaw, Patrick Burns, Sundar Dorai-Raj and Matthiew Wiener for
the answers to my puzzles. Here is a summary:

** The original question: **

 Dear R users,
 
 can someone help with these short puzzles?
 
 1) Is there a function like outer() that evaluates a three-argument
 function
 on a threedimensional grid - or else how to define such a function, say,
 outer.3()? E.g., calculate (x/y)^z on (x,y,z) element of
 {1,2,3}x{3,4}x{4,5}
 and
 return the results in a 3-dimensional array. I would naively use outer()
 on
 two of the arguments within a for() loop for the third argument and
 somehow
 glue the array together. Is there a better way? What about outer.4(), or
 even
 outer.n(), generalizing outer() to functions with an arbitrary number of
 arguments?
 
 2)
 Define a function dimnames.outer() such that dimnames.outer(x, y, *)
 returns, for x - 1:2, y - 2:3, the following matrix:
 
y
 x   2 3
   1 2 3
   2 4 6
 
 (Or does such such a function already exist?)
 
 3)
 
 How to combine puzzle 1 and puzzle 2? A function dimnames.outer.n() would
 be
 a nice little tool.
 
 4)
 
 How can I access, within a function, the name of a variable that I have
 passed to the function? E.g., letting a - 2, and subsequently calling
 function
 f(a) as defined below,
 
 f - function (x) {
   # How can I get a out of x?
 }
 
 5)
 
 Finally: Letting x - 2, how can I transform x+y into 2+y (as some
 suitable object), or generally func(x,y) into func(2,y)?
 
 Many thanks,
 Marc
 

 Answer to 5 **

The solution is of course 

substitute(func(x, y), list(x = 2))

 Answer to 4 **

This was easy, too:

deparse(substitute(x))

* Answer to 1 in easy situations 

Where the three arguments are easily isolated, outer() can be used twice:

outer(outer(a,b, /),c,^)

 Answer to 1, 2 and 3 **

A valuable idea came from Sundar Dorai-Raj who uses expand.grid() and then
transforms the grid into a matrix. Here is his code:

outer.3 - function(x, y, z, FUN, ...) {
   print(deparse(substitute(x))) # for question 2
   n.x - NROW(x)
   n.y - NROW(y)
   n.z - NROW(z)
   nm.x - if(is.array(x)) dimnames(x)[[1]] else names(x)
   nm.y - if(is.array(y)) dimnames(y)[[1]] else names(y)
   nm.z - if(is.array(z)) dimnames(z)[[1]] else names(z)
   X - expand.grid(x = x, y = y, z = z)
   f - FUN(X$x, X$y, X$z, ...)
   array(f, dim = c(n.x, n.y, n.z),
 dimnames = list(nm.x, nm.y, nm.z))
}

a - 1:3
b - 3:4
c - 4:5
names(a) - a
names(b) - b
names(c) - c
outer.3(a, b, c, function(x, y, z) (x/y)^z)
outer.3(as.matrix(a), as.matrix(b), as.matrix(c),
 function(x, y, z) (x/y)^z)

Finally, I have included the following code in my Rprofile. Here only vector
arguments are allowed, the dimnames are handeled in a slightly different
manner, and the choice of creating dimnames is controlled by the logical
argument dn.

outer.2 - function (x, y, f, dn=TRUE, ...) {
  if (!(is.vector(x)  is.vector(y)  is.numeric(x)  is.numeric(y))) {
stop(arguments not numeric vectors)
  }
  ### The suitability of f is not checked ###
  result - outer(x, y, f, ...)
  if (dn) {
lab.x   - deparse(substitute(x))
lab.y   - deparse(substitute(y))
dimnames(result)- list(x, y)
names(dimnames(result)) - c(lab.x, lab.y)
  }
  result
}

outer.3 - function(x, y, z, f, dn=TRUE, ...) {
  if (!(is.vector(x)  is.vector(y)  is.vector(z) 
 is.numeric(x)  is.numeric(y)  is.numeric(z))) {
  stop(arguments not numeric vectors)
  }
  ### The suitability of f is not checked ###
  X - expand.grid(x=x, y=y, z=z)
  temp - f(X$x, X$y, X$z, ...)
  result - array(temp, dim = c(length(x), length(y), length(z)))
  if (dn) {
 lab.x   - deparse(substitute(x))
 lab.y   - deparse(substitute(y))
 lab.z   - deparse(substitute(z))
 dimnames(result)- list(x, y, z)
 names(dimnames(result)) - c(lab.x, lab.y, lab.z)
  }
  result
}

A similar function outer.4() is straightforward.

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RE: [R] unz()

2003-07-11 Thread Marsland, John
I've solve my own problem! apologies.

For the record:

the filename argument should include the full path of the file within the
directory structure of the zip file.

but there seeks to be an issue with readLines:

 readLines(z,2)
Error in readLines(z, 2) : seek not enabled for this connection

readLines(z) works fine for the whole file, but unfortunately you cannot use
things like read.table etc.


 -Original Message-
 From: Marsland, John [mailto:[EMAIL PROTECTED]
 Sent: 11 July 2003 11:44
 To: 
 Subject: [R] unz()
 
 
 
 I am having problems getting the unz() function to work as a 
 connection to
 start reading a file...
 
 z - unz(c:/temp/stoxx.zip, close_tmi_components.txt, r)
 readLines(z,2)
 
 yields the following problems:
 
  z - unz(c:/temp/stoxx.zip, close_tmi_components.txt, r)
 Error in unz(c:/temp/stoxx.zip, close_tmi_components.txt, r) : 
 unable to open connection
 In addition: Warning message: 
 cannot locate file `close_tmi_components.txt' in zip file
 `c:/temp/stoxx.zip' 
  readLines(z,2)
 Error in readLines(z, 2) : cannot open the connection
 In addition: Warning message: 
 cannot locate file `close_tmi_components.txt' in zip file
 `c:/temp/stoxx.zip' 
 
 can anybody offer any advice?
 
 Regards,
 
 John Marsland
 
 
 **
  
 This is a commercial communication from Commerzbank AG.\ \ 
 T...{{dropped}}
 
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This is a commercial communication from Commerzbank AG.\ \ T...{{dropped}}

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[R] metapost device in R (again ;-)

2003-07-11 Thread Tamas Papp
Hi,

I read the 2000 thread on a MetaPost device in R. If I understand
correctly, the main problem with the concept is that R wants the device
driver to give back information on the size of strings/labels.

To the bet of my knowledge, MetaPost _does_ make it possible to
measure the bounding box of text (see section 7.3: Measuring text in
the MetaPost manual). For example, one could get the size of the
bounding box of btex $\int_a^b x^2$ etex -- would that be enough to
make an implementation possible? Or are the size of individual
characters and kerning information necessary?

Another question: can graphics devices be implemented solely in R (ie
without writing C code)? I realize that it will be much slower, but
first I would like to see how it works before writing in C. What
source files should I be looking at?

You may ask why I should bother about using Metapost. Well, I'd like
my TeX documents to be more consistent typographically, and MP has
quite a lot of useful features (such as the possibility to include its
eps output in LaTeX directly, EVEN when generating PDF files with
latexpdf). But the biggest bonus would clearly be the ability to
typeset math formulas nicely. (I realize that this would require one
to start a MetaPost process, but IMO the benefits would be worth the
overhead).

Is anyone else interested in a MetaPost device?

Thanks,

Tamas

-- 
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E-mail: [EMAIL PROTECTED] (preferred, especially for large messages)
[EMAIL PROTECTED]
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[R] How to plot a scatter-plot matrix?

2003-07-11 Thread Feng Zhang
Hey, R-listers

I am going to plot a scatter-plot matrix using R.
For example, give a matrix X=[x1, x2, ..., xn]
where each xi is a column vector, how to plot
all the pair scatter-plots between two different
xi and xj?

Is PAIRS able to achieve this function?

Thanks for your help.

Fred

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[R] 3d plot with different levels done in different colors

2003-07-11 Thread Tamas Papp
I would like a 3d plot of a matrix such that individual trapezoids
that make up the surface are colored according to the z-value of that
point (or preferably the midpoint of its four corners, or something
similar). MS Excel has something like that.

I know that persp can have an nx by ny matrix its col argument, I
just don't know how to generate that matrix. To calculate the midpoint
of the tiles for the matrix z, I could use something like

zz - (z[-1,-1] + z[-1,-nrow(z)] + z[-ncol(z),-1] + z[-ncol(z),-nrow(z)])/4

but I don't know how to assign a color to that value. For example if I
have

boundaries - c(0, .5, 1, 1.5)

and 

colors - c(red, green, blue)

I am looking for a function that assigns red to the elements of zz
between 0 and .5, etc. Alternative solutions are welcome, maybe
somebody has already wrote a library that does the whole thing neatly.

Thanks,

Tamas

-- 
Tamás K. Papp
E-mail: [EMAIL PROTECTED] (preferred, especially for large messages)
[EMAIL PROTECTED]
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Re: [R] info

2003-07-11 Thread Douglas Bates
Andrea Calandra [EMAIL PROTECTED] writes:

 I'm a student in chemical engineering, and i have to implement an algoritm about 
 FIVE PARAMETERS INTERPOLATION for a calibration curve (dose, optical density)
 
 y = a + (c - a) /(1+ e[-b(x-m])
 
 where
 x = ln(analyte dose + 1)
 y = the optical absorbance data
 a = the curves top asymptote
 b = the slope of the curve
 c = the curves bottom asymptote
 m = the curve X intercept
 
 Have you never seen this formula, because i don't fine information or
 lecterature about solution of this!!!

This is one parameterization of the four-parameter logistic growth
curve.  A slightly different version is available as the selfStart
model SSfpl in the nls package.  In R try

library(nls)
?SSfpl
example(SSfpl)

to see how nls and SSfpl can be used.  The example even produces a
figure for you showing what the SSfpl parameters represent.

A literature reference for the SSfpl form of the four-parameter
logistic is Appendix C.6 in Pinheiro and Bates (2000), Mixed-effects
Models in S and S-PLUS, Springer.

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Re: [R] hazard estimate

2003-07-11 Thread Thomas Lumley
On Fri, 11 Jul 2003, Ruud H. Koning wrote:

 library(survival)
 ?basehaz

 gives

   For `basehaz', a dataframe with the baseline hazard, times, and
  strata.



Yes, but that's the cumulative hazard, not the hazard rate.

-thomas

Thomas Lumley   Assoc. Professor, Biostatistics
[EMAIL PROTECTED]   University of Washington, Seattle

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[R] using SVD to get an inverse matrix of covariance matrix

2003-07-11 Thread ge yreyt
Dear R-users,

I have one question about using SVD to get an inverse
matrix of covariance matrix

Sometimes I met many singular values d are close to 0:
look this example

$d
 [1] 4.178853e+00 2.722005e+00 2.139863e+00
1.867628e+00 1.588967e+00
 [6] 1.401554e+00 1.256964e+00 1.185750e+00
1.060692e+00 9.932592e-01
[11] 9.412768e-01 8.530497e-01 8.211395e-01
8.077817e-01 7.706618e-01
[16] 7.007119e-01 6.237449e-01 5.709922e-01
5.550645e-01 5.062633e-01
[21] 4.792278e-01 4.222183e-01 3.660419e-01
3.293667e-01 3.026312e-01
[26] 2.942821e-01 2.811098e-01 2.626359e-01
2.199134e-01 1.943776e-01
[31] 1.712359e-01 1.561616e-01 1.359116e-01
1.280704e-01 1.099847e-01
[36] 1.013633e-01 9.622151e-02 8.396722e-02
7.083654e-02 6.755967e-02
[41] 5.392306e-02 3.807169e-02 2.942905e-02
2.726249e-02 4.555067e-16
[46] 3.095299e-16 2.918951e-16 2.672369e-16
2.336190e-16 2.239488e-16
[51] 2.089471e-16 1.970283e-16 1.863823e-16
1.775903e-16 1.698164e-16
[56] 1.594850e-16 1.500927e-16 1.469157e-16
1.406057e-16 1.366468e-16
[61] 1.319553e-16 1.252144e-16 1.193341e-16
1.142526e-16 1.064905e-16
[66] 1.040117e-16 1.005124e-16 9.310727e-17
8.995158e-17 8.529797e-17
[71] 8.204344e-17 7.759612e-17 7.478445e-17
7.225679e-17 6.709050e-17
[76] 5.996665e-17 5.830386e-17 5.687619e-17
5.121094e-17 4.848857e-17
[81] 4.549679e-17 4.307547e-17 3.830520e-17
3.450571e-17 3.312035e-17
[86] 3.260300e-17 2.399392e-17 2.141970e-17
1.996962e-17 1.881993e-17
[91] 1.567323e-17 1.062695e-17 6.730278e-18
2.118570e-18 4.991002e-19

Since the inverse matrix = u * inverse(d) * v',
If I calculate inverse d based on formula : 1/d, then
most values of inverse matrix
will be huge. This must be not a good way. MOre
special case, if a single value is 0, then
we can not calculate inverse d based on 1/d.

Therefore, my question is how I can calculate inverse
d (that is inverse diag(d) more efficiently???


Thanks

ping


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Re: [R] How to plot a scatter-plot matrix?

2003-07-11 Thread Gavin Simpson
Fred,

[from help on pairs() ]:

...
Arguments:
   x: the coordinates of points given as columns of a matrix.

So yes, pairs will do what you ask.  See ?pairs for more info.

Also you might consider the alternative function from the lattice package:

 library(lattice)   #load lattice graphics package
 ?splom #help for splom()
Which is called differently using a formula interface.

HTH

G

Feng Zhang wrote:

Hey, R-listers

I am going to plot a scatter-plot matrix using R.
For example, give a matrix X=[x1, x2, ..., xn]
where each xi is a column vector, how to plot
all the pair scatter-plots between two different
xi and xj?
Is PAIRS able to achieve this function?

Thanks for your help.

Fred

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ENSIS Research Fellow [F] +44 (0)20 7679 7565
ENSIS Ltd.  ECRC [E] [EMAIL PROTECTED]
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Re: [R] Offsets in glmmPQL?

2003-07-11 Thread Douglas Bates
Anon. [EMAIL PROTECTED] writes:

 I've got a colleague who's using a GLMM to analyse her data, and I've
 told her that she needs to include an offset.  However, glmmPQL
 doesn't seem to allow one to be included.  Is there anyway of doing
 this?

We just discovered and fixed a similar problem in the GLMM function in
the lme4 package.  I have uploaded the 0.2-4 release of lme4 to CRAN.
Please wait a few days for it to be transferred to the packages
directory and for a Windows package to be created then try it.
Remember to check for version 0.2-4 or later.

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Re: [R] using SVD to get an inverse matrix of covariance matrix

2003-07-11 Thread Jerome Asselin

If some of the eigenvalues of a square matrix are (close to) zero, then 
it's inverse does not exist. However, you can always calculate it's 
generalized inverse ginv().

library(MASS)
help(ginv)

It'll allow you to specify a tol argument:
 tol: A relative tolerance to detect zero singular values.

Hope that helps,
Jerome

On July 11, 2003 08:49 am, ge yreyt wrote:
 Content-Length: 2154
 Status: R
 X-Status: N

 Dear R-users,

 I have one question about using SVD to get an inverse
 matrix of covariance matrix

 Sometimes I met many singular values d are close to 0:
 look this example


snip


 Since the inverse matrix = u * inverse(d) * v',
 If I calculate inverse d based on formula : 1/d, then
 most values of inverse matrix
 will be huge. This must be not a good way. MOre
 special case, if a single value is 0, then
 we can not calculate inverse d based on 1/d.

 Therefore, my question is how I can calculate inverse
 d (that is inverse diag(d) more efficiently???


 Thanks

 ping


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[R] Constraining asymptote in SSasymp

2003-07-11 Thread Martin Biuw
Hi all,
Is there a simple way to constrain the Asym argument in the SSasymp 
function so that it does not exceed some maximum value?

Thanks!

Martin

--
Martin Biuw
Sea Mammal Research Unit
Gatty Marine Laboratory, University of St Andrews
St Andrews, Fife KY16 8PA
Scotland
Ph: +44-(0)1334-462637
Fax: +44-(0)1334-462632
Web: http://smub.st.and.ac.uk
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[R] Indexing with NA as FALSE??

2003-07-11 Thread ted . harding
Hi Folks,

Example:
t-c(1,2,3,4,5,6,7,8,9)
u-c(1,NA,3,NA,5,NA,7,NA,9)
t[u==5]
-- NA NA 5 NA NA

Now, if I could somehow set things so that NA was FALSE for
indexing, then
t[u==5]
-- 5

I know I can do it with
t[(u==5)(!is.na(u))]
but in the situation I am dealing with this leads to massively
cumbersome, typo-prone and hard-to-read code.

Also, as an extra, it would be very useful if, for instance,
t[u==NA] -- 2 4 6 8
(I realise that working round this is less cumbersome, but even so).

What I'm really trying to work round is the don't know way that R
handles NA. Reasonable in the logical sence, in that in the first
example R is saying Can't tell whether u[2], u[4], u[6], u[8]
are equal to 5 or not, so will return a result which represents
this uncertainty, and in the second You're telling me you don't
know what value you want to match, so ... .

Instead of that, since NA is one of the three values TRUE, FALSE, NA
of a logical, I'd like to be able to (a) treat NA as FALSE, (b) test
for a match between NA (as specified by me) and NA (as the value of
a logical variable).

Is there any non-cumbersome way to achieve this?

With thanks,
Ted

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Re: [R] Indexing with NA as FALSE??

2003-07-11 Thread Barry Rowlingson
[EMAIL PROTECTED] wrote:

I know I can do it with
t[(u==5)(!is.na(u))]
but in the situation I am dealing with this leads to massively
cumbersome, typo-prone and hard-to-read code.
 You could redefine '[' or '==', but that would lead to massively 
dangerous code. Anything could happen. Anyone who writes code that 
redefines such basic stuff may need their head examined.

 I think you are going to have to work round it with the !is.na(u) 
thing, but you could wrap it up in a function:

true4sure-function(v){v  !is.na(v)}

then

 t[true4sure(u==5)]
[1] 5
 although perhaps you could give it a less whimsical name

Also, as an extra, it would be very useful if, for instance,
t[u==NA] -- 2 4 6 8
(I realise that working round this is less cumbersome, but even so).
 Here is a way of doing that. It redefines '=='. It will break things 
that depend on NA's remaining NA's in comparisons. Do not use this code. 
Do not even let it pollute your files. Consider it a dangerous virus:

assign(==,function(a,b){a[is.na(a)]-FALSE; b[is.na(b)]-FALSE; get(==,package:base)(a,b)})
 and then you get:

c(1,2,3,NA,NA,NA) == c(1,NA,2,NA,NA,4)
[1]  TRUE FALSE FALSE  TRUE  TRUE FALSE

Instead of that, since NA is one of the three values TRUE, FALSE, NA
of a logical, I'd like to be able to (a) treat NA as FALSE, (b) test
for a match between NA (as specified by me) and NA (as the value of
a logical variable).
 Thats what it does. Of course it has a bug/feature in that NA is now 
== to FALSE But then you arent going to use that code.

 Safer would be to define a new binary operator:

 assign(%=na%,function(a,b){a[is.na(a)]-FALSE; b[is.na(b)]-FALSE; 
 get(==,package:base)(a,b)})

 Then you can do:

 c(1,2,3,NA,NA,NA) %=na% c(1,NA,2,NA,NA,4)
[1]  TRUE FALSE FALSE  TRUE  TRUE FALSE
 again this has the same NA==FALSE property.

 Here's a truth table for that operator:

 outer(c(T,F,NA),c(T,F,NA),%=na%)
  [,1]  [,2]  [,3]
[1,]  TRUE FALSE FALSE
[2,] FALSE  TRUE  TRUE
[3,] FALSE  TRUE  TRUE
 You just need to write an operator that returns TRUE on the diagonal 
only Easy modification of %=na% but its late on a Friday and I have 
a poker game to attend...

 Did I say not to use my code that redefines '=='? Well dont use it. Ever.

Baz

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Re: [R] Indexing with NA as FALSE??

2003-07-11 Thread Thomas Lumley
On Fri, 11 Jul 2003 [EMAIL PROTECTED] wrote:

 Hi Folks,

 Example:
 t-c(1,2,3,4,5,6,7,8,9)
 u-c(1,NA,3,NA,5,NA,7,NA,9)
 t[u==5]
 -- NA NA 5 NA NA

 Now, if I could somehow set things so that NA was FALSE for
 indexing, then
 t[u==5]
 -- 5

t[u %in% 5]


 I know I can do it with
 t[(u==5)(!is.na(u))]
 but in the situation I am dealing with this leads to massively
 cumbersome, typo-prone and hard-to-read code.

 Also, as an extra, it would be very useful if, for instance,
 t[u==NA] -- 2 4 6 8

t[ u %in% NA]


-thomas

Thomas Lumley   Assoc. Professor, Biostatistics
[EMAIL PROTECTED]   University of Washington, Seattle

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[R] three short questions

2003-07-11 Thread javier garcia - CEBAS
Hi all;

This is my first message to the list, and I've got three basic questions:

How could I insert comments in a file with commands to be used as source in R?

Is it possible to quickly display a window with all the colors available in 
colors()? How?

I'm displaying points, but they overlap, wether points() uses triangles, 
bullets or whatever. Is it possible to change (diminish) the size of the 
symbols? 

Thanks all,

Javier

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[R] Question regarding irts class

2003-07-11 Thread Luis Torgo
I'm using the new irts class from package tseries which I find quite useful.
However, I have data of different type being sample at irregular times (i.e. 
my data is more of a data frame than a matrix).
Function irts that is used to create irts objects demands that the value 
component is either a vector or a matrix. Is there any reason for not 
allowing it to be a data frame? Looking at the code of this function it seems 
straightforward to allow the function to accept data frames, but maybe there 
is some reason for not allowing this that I'm not aware.
Thanks,
Luis Torgo

-- 
Luis Torgo
FEP/LIACC, University of Porto   Phone : (+351) 22 607 88 30
Machine Learning Group   Fax   : (+351) 22 600 36 54
R. Campo Alegre, 823 email : [EMAIL PROTECTED]
4150 PORTO   -  PORTUGAL WWW   : http://www.liacc.up.pt/~ltorgo

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Re: [R] three short questions

2003-07-11 Thread J.R. Lockwood
 
 This is my first message to the list, and I've got three basic questions:
 
 How could I insert comments in a file with commands to be used as source in R?

use the pound sign #

 
 Is it possible to quickly display a window with all the colors available in 
 colors()? How?
 

I've got such a thing on my web page, though it may be dated

http://www.rand.org/methodology/stat/members/lockwood/downloads/R-built-in-colors.pdf


 I'm displaying points, but they overlap, wether points() uses triangles, 
 bullets or whatever. Is it possible to change (diminish) the size of the 
 symbols? 
 

yes; use pch to change symbols and cex to change sizes of symbols.
See the help page for par

J.R. Lockwood
412-683-2300 x4941
[EMAIL PROTECTED]
http://www.rand.org/methodology/stat/members/lockwood/

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[R] Reading data from the console

2003-07-11 Thread Doru Cojoc
I want to be able to write a program in R that does the following:
- it allows the user to enter the dimensions of the matrix from the
console
- it allows the user then to enter each element of the matrix from the
console.

I am looking for an equivalent for the C++ command read, or read.ln.
read.table would not work, since the data is not in a table and,
furthermore, since the data does not exist prior to the execution of the
program; the user has to be able to introduce the data from the console.
scan would not work either. For example, in the following bit of code

cat('Number of populations:', '\n')
m-scan(,n=1, quiet=TRUE)
cat('Number of categories:', '\n')
k-scan(,n=1, quiet=TRUE)
N-matrix(0,m,k)
for(i in 1:m) for(j in 1:k) {
 N[i,j]-scan(,n=1, quiet=TRUE)
 }

scan will take m to be the next command rather than wait for me to
introduce the number I want for m.

Any ideas? Thanks a lot!

Doru Cojoc

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Re: [R] Reading data from the console

2003-07-11 Thread Jerome Asselin

Put your code in a function. See below.

Cheers,
Jerome

mat - function()
{
cat('Number of populations:', '\n')
m-scan(,n=1, quiet=TRUE)
cat('Number of categories:', '\n')
k-scan(,n=1, quiet=TRUE)
N-matrix(0,m,k)
for(i in 1:m) for(j in 1:k) {
 N[i,j]-scan(,n=1, quiet=TRUE)
 }
N
}

 mat()
Number of populations:
1: 2
Number of categories:
1: 2
1: 1
1: 2
1: 3
1: 4
 [,1] [,2]
[1,]12
[2,]34



On July 11, 2003 01:29 pm, Doru Cojoc wrote:
 I want to be able to write a program in R that does the following:
 - it allows the user to enter the dimensions of the matrix from the
 console
 - it allows the user then to enter each element of the matrix from the
 console.

 I am looking for an equivalent for the C++ command read, or read.ln.
 read.table would not work, since the data is not in a table and,
 furthermore, since the data does not exist prior to the execution of the
 program; the user has to be able to introduce the data from the console.
 scan would not work either. For example, in the following bit of code

 cat('Number of populations:', '\n')
 m-scan(,n=1, quiet=TRUE)
 cat('Number of categories:', '\n')
 k-scan(,n=1, quiet=TRUE)
 N-matrix(0,m,k)
 for(i in 1:m) for(j in 1:k) {
  N[i,j]-scan(,n=1, quiet=TRUE)
  }

 scan will take m to be the next command rather than wait for me to
 introduce the number I want for m.

 Any ideas? Thanks a lot!

 Doru Cojoc

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Re: [R] three short questions

2003-07-11 Thread Marc Schwartz
On Fri, 2003-07-11 at 12:27, J.R. Lockwood wrote:
  
  This is my first message to the list, and I've got three basic questions:
  
  How could I insert comments in a file with commands to be used as source in R?
 
 use the pound sign #
 
  
  Is it possible to quickly display a window with all the colors available in 
  colors()? How?
  
 
 I've got such a thing on my web page, though it may be dated
 
 http://www.rand.org/methodology/stat/members/lockwood/downloads/R-built-in-colors.pdf
 
 
  I'm displaying points, but they overlap, wether points() uses triangles, 
  bullets or whatever. Is it possible to change (diminish) the size of the 
  symbols? 
  
 
 yes; use pch to change symbols and cex to change sizes of symbols.
 See the help page for par


A couple other possibilities on your third query, depending upon the
nature of your data and the type of plot you are using:

1. Adjust the limits of the x and/or y axis in your plot to enhance the
separation of the points. Generally, this can be done with the 'xlim'
and/or 'ylim' arguments to your plotting function. For example, see
?plot.default for more information.

2. You can try to use jitter() [ie. plot(jitter(x), jitter(y))] if you
have a lot of points that overlap at common coordinates. This introduces
a level of 'noise' to the x and/or y values and can result in a level of
dispersion of these points. See ?jitter for more information. This can
result in a visual clustering of points, so keep that in mind.

Be aware that each of the above can impact in a positive or deleterious
fashion, the visual presentation and interpretation of your data so
proceed with caution.

HTH,

Marc Schwartz

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Re: [R] using SVD to get an inverse matrix of covariance matrix

2003-07-11 Thread Spencer Graves
	  More presicely, if M is singular, then M%*%x = b will have multiple 
solutions only if b is in the subspace spanned by columns of M.

	  Example:

 M - array(1:2, dim=c(2,2))
 (svdM - svd(M))
$d
[1] 3.162278 0.00
$u
   [,1]   [,2]
[1,] -0.4472136 -0.8944272
[2,] -0.8944272  0.4472136
$v
   [,1]   [,2]
[1,] -0.7071068 -0.7071068
[2,] -0.7071068  0.7071068
	  This M is not symmetrical and so cannot be a covariance matrix, but 
you can get the same effect with a symmetrical matrix.  I'm using this 
example because it is the simplest thing that comes to mind to 
illustrate the point.

	  By the definition of the singular value decomposition, M = svdM$u %*% 
diag(svdM$d) %*% t(svdM$v).  Since svdM$d[2] == 0,

  M%*%x = svdM$u[, 1]*svdM$d[1]*t(svdM$v[,1])%*%x
= x1 * svdM$u[,1],
where
  x1 = svdM$d[1]*t(svdM$v[,1])%*%x
	  Thus, if b is proportional to svdM$u[,1], the system has a solution. 
 That solution will be proportional to svdM$v[,1] + x2*svdM$v[,2], for 
any arbitrary value of x2.

hope this helps.
spencer graves
Thomas Lumley wrote:
On Fri, 11 Jul 2003, ge yreyt wrote:


Dear R-users,

I have one question about using SVD to get an inverse
matrix of covariance matrix
Sometimes I met many singular values d are close to 0:
look this example


snip

most values of inverse matrix
will be huge. This must be not a good way. MOre
special case, if a single value is 0, then
we can not calculate inverse d based on 1/d.
Therefore, my question is how I can calculate inverse
d (that is inverse diag(d) more efficiently???


If singular values are zero the matrix doesn't have an inverse: that is,
the equation   Mx=b  will have multiple solutions for any given b.
It is possible to get a pseudoinverse, a matrix M that picks out one of
the solutions.  One way to do this is to set the diagonal to 1/d where d
is not (nearly) zero and to 0 when d is (nearly) zero. One place to find a
discussion of this is `Matrix Computations' by Golub and van Loan.
	-thomas

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RE: [R] postscript/eps label clipping

2003-07-11 Thread drf5n
On Fri, 11 Jul 2003, Mulholland, Tom wrote:

 I guess I was wrong there. However it does seem that it will come down
 to fontsize 9 without clipping (or if it does I find it hard to see).

Thanks.  It seemed like that is the way it was working, but it also seems
counterintuitive: reduced pointsizes in postscript output make the graphs
bigger, up to a point, after which the letters are too big(small?) to fit
without clipping.

Thanks again,
Dave.
-- 
 Dave Forrest(434)924-3954w(111B) (804)642-0662h (804)695-2026p
 [EMAIL PROTECTED]http://mug.sys.virginia.edu/~drf5n/

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[R] getAnyhwhere behavior

2003-07-11 Thread Cliff Lunneborg
I would have expected the function getAnywhere to have behaved
differently in the following:

 search()
 [1] .GlobalEnv  file:C:/R/Rdata/miya/.Rdata
 [3] package:bootpackage:methods
 [5] package:ctest   package:mva
 [7] package:modreg  package:nls
 [9] package:ts  Autoloads
[11] package:base

 getAnywhere(basic.ci)
Error in getAnywhere(basic.ci) : Object basic.ci not found

 basic.ci-get(basic.ci,environment(boot))

 getAnywhere(basic.ci)
A single object matching `basic.ci' was found
It was found in the following places
  .GlobalEnv
  registered S3 method for basic from namespace boot
  namespace:boot
with value

function (t0, t, conf = 0.95, hinv = function(t) t)
{
qq - norm.inter(t, (1 + c(conf, -conf))/2)
out - cbind(conf, matrix(qq[, 1], ncol = 2), matrix(hinv(2 *
t0 - qq[, 2]), ncol = 2))
out
}
environment: namespace:boot

Why did getAnywhere not see basic.ci in the environment from which I
got it?

**
Cliff Lunneborg, Professor Emeritus, Statistics 
Psychology, University of Washington, Seattle
[EMAIL PROTECTED]

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[R] spdep

2003-07-11 Thread Mark Piorecky
Hi everyone,

The Spatial Dependence (spdep) library, has a function called 'dnearneigh', which 
identifies neighbours of region points by Euclidean distance between lower (greater 
than) and upper (less than or equal to) bounds.  The function returns a list of 
integer vectors giving the region id numbers for neighbours satisfying the distance 
criteria.

I have used this to identify the euclidean distance of all points falling within 
0-2000m of each of my surveys locations.  Once distances are converted to inverse 
euclidean distances, the list looks something like this:

[[1]]
[1] 15.617376  0.535176  0.569497

[[2]]
[1] 15.6173762  0.5415378  0.5773159

[[3]]
[1] NA
 
etc.

For each of these points I also have presence/absence data for a particular owl 
species (all the location, PA, etc. is kept in a single data frame).  Is there a way 
of creating a similar list to the one above, identifying the Presence or Absence of an 
owl at each of the points that fall with in 0-2000m of the interested site??

I am attempting to determine the following equation for each site, at a number of 
spatial lags, i.e. 0-2000, 0-4000, etc
   
Autocovariatei =  Sum wij  yj / Sum wij  

 

Variables: Autocovariate for stop i   

yj = Presence (1) or Absence (0) at stop j

wij = the inverse Euclidean distance between stops i 
and j 

Any help would be greatly appreciated.

Mark
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Re: [R] 3d plot with different levels done in different colors

2003-07-11 Thread Jerome Asselin

Hi,

Consider this example which I have modified from the persp() help file.
It uses topo.colors() to create a series of colors.

Cheers,
Jerome

 x - seq(-10, 10, length= 30)
 y - x
 f - function(x,y) { r - sqrt(x^2+y^2); 10 * sin(r)/r }
 z - outer(x, y, f)
 z[is.na(z)] - 1
 op - par(bg = white)
 zz - (z[-1,-1] + z[-1,-ncol(z)] + z[-nrow(z),-1] + 
  z[-nrow(z),-ncol(z)])/4
 cols - topo.colors(length(zz))
 cols[order(zz)] - cols
 persp(x, y, z, theta = 30, phi = 30, expand = 0.5, col = cols)


On July 11, 2003 08:26 am, Tamas Papp wrote:
 Content-Length: 1223
 Status: R
 X-Status: N

 I would like a 3d plot of a matrix such that individual trapezoids
 that make up the surface are colored according to the z-value of that
 point (or preferably the midpoint of its four corners, or something
 similar). MS Excel has something like that.

 I know that persp can have an nx by ny matrix its col argument, I
 just don't know how to generate that matrix. To calculate the midpoint
 of the tiles for the matrix z, I could use something like

 zz - (z[-1,-1] + z[-1,-nrow(z)] + z[-ncol(z),-1] +
 z[-ncol(z),-nrow(z)])/4

 but I don't know how to assign a color to that value. For example if I
 have

 boundaries - c(0, .5, 1, 1.5)

 and

 colors - c(red, green, blue)

 I am looking for a function that assigns red to the elements of zz
 between 0 and .5, etc. Alternative solutions are welcome, maybe
 somebody has already wrote a library that does the whole thing neatly.

 Thanks,

 Tamas

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[R] How to generate regression matrix with correlation matrix

2003-07-11 Thread rui
Dear R community:

I want to simulate a regression matrix which is generated from an orthonormal matrix X 
of dimension 30*10 with different between-column pairwise correlation coefficients 
generated from uniform distribution U(-1,1).

Thanks in advance!

Rui
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Re: [R] How to generate regression matrix with correlation matrix

2003-07-11 Thread Spencer Graves
	  What problem are you really trying to solve?  The problem statement 
as I read it contains two logical contradictions that I see:

	  1.  Orthonormal means X'X = Identity matrix (10 x 10).  That means 
the pairwise correlation coefficients can NOT be different from 0.

	  2.  Not all symmetric matrices with 1's on the diagonal and random 
numbers U(-1, 1) on the off diagonal are correlation matrices.  Consider 
the following example:

 Cormat - array(c(1, -0.9, -0.9, -0.9, 1, -0.9, -0.9, -0.9, 1), 
dim=c(3,3))
 Cormat
 [,1] [,2] [,3]
[1,]  1.0 -0.9 -0.9
[2,] -0.9  1.0 -0.9
[3,] -0.9 -0.9  1.0
 eigen(Cormat)
$values
[1]  1.9  1.9 -0.8

The fact that one eigenvalue is negative means that this Cormat is not 
positive definite.

hope this helps.  spencer graves

rui wrote:
Dear R community:

I want to simulate a regression matrix which 
is generated from an orthonormal matrix X of
dimension 30*10 with different between-column
pairwise correlation coefficients generated from
uniform distribution U(-1,1).
Thanks in advance!

Rui
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[R] ss's are incorrect from aov with multiple factors

2003-07-11 Thread John Christie
Hi,
	I have been trying to work with error terms given back from aov to 
make confidence intervals.  However, the numbers seem to be incorrect.  
If there is more than one term in the ANOVA then the error terms can be 
inflated by the number of factors in the extra terms.  The F's are 
correct so it is right back to the SS.  I was wondering if this is 
standard practice for stats programs or unique to R?

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[R] More clear statement about the question of how to generateregression matrix with correlation matrix

2003-07-11 Thread rui
Dear R community:

I am trying to do a simulation study mentioned by Fu (1998), Journal of Computational 
and Graphical Statistics, Volume7, Number 3, Page 397-416. In order to give a clear 
statement of quesion I copy the following paragraph from the article: We compare the 
bridge model with the OLS, the lasso and the ridge in a simulation of a linear 
regression model of 30 observations and 10 regressors Y = beta0 + beta1*x1 + ... + 
beta10*x10 + epsilon, where epsilon follows a normal distribution with mean mu and 
standard deviation sigma. Ten regression matrices {X}m, m=1,...,10, are generated from 
an orthonormal matrix X of dimension 30*10 with different between-column pairwise 
correlation coefficients {rho}m generated from uniform distribution U(-1, 1).

Thanks in advance.

Rui
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Re: [R] ss's are incorrect from aov with multiple factors

2003-07-11 Thread JRG
On 11 Jul 03, at 21:20, John Christie wrote:

 Hi,
   I have been trying to work with error terms given back from aov to 
 make confidence intervals.  However, the numbers seem to be incorrect.  
 If there is more than one term in the ANOVA then the error terms can be 
 inflated by the number of factors in the extra terms.  The F's are 
 correct so it is right back to the SS.  I was wondering if this is 
 standard practice for stats programs or unique to R?
 
 __
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In what sense are the SSs incorrect, exactly?  And what do you think the correct 
values should be?

---JRG


John R. Gleason
Associate Professor

Syracuse University
430 Huntington Hall  Voice:   315-443-3107
Syracuse, NY 13244-2340  USA FAX: 315-443-4085

PGP public key at keyservers

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Re: [R] More clear statement about the question of how to generateregression matrix with correlation matrix

2003-07-11 Thread Spencer Graves
Dear Rui:

	  If noone else responds, I suggest you forward my earlier comments to 
Fu and ask him.

Spencer Graves

rui wrote:
Dear R community:

I am trying to do a simulation study mentioned by Fu (1998), 
Journal of Computational and Graphical Statistics, Volume7,
Number 3, Page 397-416. In order to give a clear statement of
quesion I copy the following paragraph from the article: We
compare the bridge model with the OLS, the lasso and the ridge
in a simulation of a linear regression model of 30 observations
and 10 regressors Y = beta0 + beta1*x1 + ... + beta10*x10 +
epsilon, where epsilon follows a normal distribution with mean
mu and standard deviation sigma. Ten regression matrices {X}m,
m=1,...,10, are generated from an orthonormal matrix X of
dimension 30*10 with different between-column pairwise
correlation coefficients {rho}m generated from uniform
distribution U(-1, 1).
Thanks in advance.

Rui
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Re: [R] ss's are incorrect from aov with multiple factors

2003-07-11 Thread John Christie
On Friday, July 11, 2003, at 09:38  PM, JRG wrote:

On 11 Jul 03, at 21:20, John Christie wrote:

In what sense are the SSs incorrect, exactly?  And what do you think 
the correct values should be?
Well, if I take the residuals for one of the main effects I should be 
able to calculate a confidence interval from it that has some 
relationship to the actual values for that effect so that an accurate 
plot can be made.  The transformation isn't too hard, I just need to 
divide them by the number of factors in the other term.  But, my 
recollection is that this isn't true for other stats packages and may 
lead people who are new and trying to calculate them for the first time 
to incorrect conclusions.  The reported values should be corrected.  
Although, my recollection could be wrong.

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Re: [R] Nonliner Rgression using Neural Nnetworks

2003-07-11 Thread kjetil brinchmann halvorsen
On 11 Jul 2003 at 18:56, Yukihiro Ishii wrote:

 Hi, 
 I am an old hand at chemistry but a complete beginner at statistics
  including R computations.
 My question is whether you can carry out nonlinear
 multivariate regression  analysis in  R using neural networks, where the
 output variable can range from -Inf to  + Inf., unlike discriminant 
 analysis where the output is confined to one  or zero. The library nnet
 seems to work only in the latter case but then I could  be wrong. 

You are wrong. nnet can be used to predict a continous variable, for 
instance  by setting the arguments linout=TRUE. 

For ways to set different types of networks, see 
?nnet

ans especially the arguments
linout
entropy
softmax
censored

Kjetil Halvorsen

 
 Please help me there.
 
 Thanks in advance.
 
 Y.Ishii [EMAIL PROTECTED]
 2-3-28 $B!! (BTsurumaki-minami, Hadano
 257-0002 Japan
 
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Re: [R] ss's are incorrect from aov with multiple factors

2003-07-11 Thread Spencer Graves
Dear John Christie:

	  People tend to get the quickest and most helpful responses when they 
provide a toy problem that produces what they think are anamolous 
results.  This increases the chances that someone will be able to 
provide a sensible answer in the few seconds they have available for 
your question.  Often, the process of preparing a toy problem leads them 
to an answer to their question.

	  Sorry I couldn't be more helpful.  spencer graves

JRG wrote:
On 11 Jul 03, at 21:20, John Christie wrote:


Hi,
	I have been trying to work with error terms given back from aov to 
make confidence intervals.  However, the numbers seem to be incorrect.  
If there is more than one term in the ANOVA then the error terms can be 
inflated by the number of factors in the extra terms.  The F's are 
correct so it is right back to the SS.  I was wondering if this is 
standard practice for stats programs or unique to R?

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In what sense are the SSs incorrect, exactly?  And what do you think the correct values should be?

---JRG

John R. Gleason
Associate Professor
Syracuse University
430 Huntington Hall  Voice:   315-443-3107
Syracuse, NY 13244-2340  USA FAX: 315-443-4085
PGP public key at keyservers

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[R] help with bivariate density plot question

2003-07-11 Thread liping
Dear R users:

I have a dataset with two variables (2 observations, two samples from same 
subject) and I used kernSur from library(Genkern) to 
get a estimated bivariate density and corresponding plots as follows:

new.data.normal-data.normal[!is.na(data.normal[,2]),]
x-new.data.normal[,2]
y-new.data.normal[,3]

op - KernSur(x,y, xgridsize=50, ygridsize=50, correlation=0.4968023, 
  xbandwidth=1, ybandwidth=1)

#3D density plot
persp(op$xvals, op$yvals, op$zden,
theta=30,phi=10,expand=0.5,ltheta=120,
xlab=TECH3661.A,ylab=TECH3661.B,zlab=Prob,col=pink,
  , main=3D DENSITY PLOT-TECH3661 , sub= TECH3661.A AND TECH3661.B,
box = T, axes = TRUE,ticktype = detailed, )

#countour plot
image(op$xvals, op$yvals, op$zden, col=terrain.colors(100), 
axes=TRUE,xlab=TECH3661.A,ylab=TECH3661.B)
points(x,y,pch=*)

Now after above step, how can I use 'contour' or other commands to draw ellipse curves 
over above plots indicating including about 68% data, including about 84% data, 
etc. similar to the (-std,std), (-2*std,2*std),(-3*std, 3*std) intervals for 
univariate variable.

any suggestin will be appreciated.

liping








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[R] ss's are incorrect from aov with multiple factors (EXAMPLE!)

2003-07-11 Thread John Christie
OK, I do see that there is a problem in my first email.  I have noticed 
this with repeated measures designs.  Otherwise, of course, there is 
only one error term for all factors.  But, with repeated measures 
designs this is not the case.

On Friday, July 11, 2003, at 10:00  PM, Spencer Graves wrote:

	  People tend to get the quickest and most helpful responses when 
they provide a toy problem that produces what they think are anamolous 
results
here is an admittedly poor example with factors a and b and s subjects.

a-factor(rep(c(0,1),12))
b-factor(rep(c(0,0,1,1),6))
s- factor(rep(1:6,each=4))
 x - c(49.5, 62.8, 46.8, 57, 59.8, 58.5, 55.5, 56, 62.8, 55.8, 69.5, 
55, 62, 48.8, 45.5, 44.2, 52, 51.5, 49.8, 48.8, 57.2, 59, 53.2, 56)

now

summary(aov(x~a*b+Error(s/(a*b

gives a table of results
but, if one wanted to generate a confidence interval for factor b one 
needs to reanalyze the results thusly

ss-aggregate(x, list(s=s, b=b), mean)
summary(aov(x~b+Error(s/b), data=ss))
This yields an error term half the size as that reported for b in the 
combined ANOVA.  I would suggest that the way the ss and MSE are 
reported is erroneous since they should be able to be used to directly 
calculate confidence intervals or make mean comparisons without having 
to collapse and reanalyze for every effect.

Furthermore, I am guessing that this problem makes it impossible to get 
a correct average MSE that includes the interaction term.  OK, far from 
impossible, but very difficult to verify that the term is correct.

NOTE  F for b is the same in the first ANOVA and the second.

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