Displaying 20 results from an estimated 900 matches similar to: "Problem on minima"
2002 Feb 25
4
replace NAs
Dear R community:
it is possible to replace NA?s in a data frame with zeroes?
what should I do?
Thanks in advance
Juan Pablo
_________________________________________________________________
MSN Photos es la manera m?s sencilla de compartir e imprimir sus fotos:
http://photos.latam.msn.com/Support/WorldWide.aspx
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2002 Mar 29
2
order()
Hi,
In the order() help file, there is an example like:
a <- c(4, 3, 2, NA, 1)
b <- c(4, NA, 2, 7, 1)
z <- cbind(a, b)
(o <- order(a, b)); z[o, ]
How can I do something like "order a in ascending order, b in descending
order"? And say I have a third vector c, and I'd like to add this to the
previous condition "a ascending, b descending, c
2002 Mar 18
4
Plot 3d
There exists a plot 3d functions (or similar) in R?
Thanks,
========================================
Cezar Freitas (ICQ 109128967)
IMECC - UNICAMP
Campinas, SP - Brasil
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2002 Mar 19
5
matrix with fix number columns but variable number rows
I have to store a number of vectors of the same length. I know the
length but I do not know the number of vectors.
How can I store them as they are created (they are created one by one)?
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Send "info", "help", or
2002 Mar 20
3
tex/latex output?
Is it possible to write the output/results (redirect) to a latex file?
Jeff.
Jeff D. Hamann
Hamann, Donald & Associates, Inc.
PO Box 1421
Corvallis, Oregon USA 97339-1421
Bus. 541-753-7333
Cell. 541-740-5988
jeff_hamann at hamanndonald.com
www.hamanndonald.com
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2002 Aug 20
4
plot and bg
Hi all,
I would like to plot some points and define the bg color of my graphics.
But the bg parameter set is defined for the. whole graphic.
In fact, i would like to use something like :
box(bg=gray(0.9)).
So, the background concerns only the plot region and not the main
title, the x title and the y title.
The option col for the function box() concerns the contour and there is
no option
2002 Feb 11
4
Multiple graph pages
Dear R users:
I am a relatively experienced Splus user but new to R, using the version
for Windows 2000.
Splus allows the user to generate multiple graph pages in the graph window.
For example, if you have two plot(...) commands in the script than two
pages in the graph window will be created. However, when I tried this in R,
the second plot will just overwrite the first plot in the graph
2003 Jan 06
1
On nlm
Dear all, I have to minimize a (real) function in a loop (say i in
(1:1000)) and store its ``$estimate'', via
l2estim<-nlm(f.minimo,c(-.01,0.1))$estimate
into a vector for further analisys.
Since the function's behaviour is quite peculiar (in the sense that in
the simulation study it may not have a minumum), sometimes I get the the
warning
Error in nlm(minimo, c(-0.01, 0.1),
2006 May 04
0
R: R: [Re:] function to replace missing values with median value?]]
oops!, I pressed the 'send' key too soon, ...
see ?replace
replace(x, is.na(x), median(x, na.rm=T))
take also a look at the function itself
> replace
function (x, list, values)
{
x[list] <- values
x
}
<environment: namespace:base>
Stefano
>-----Messaggio originale-----
>Da: r-help-bounces at stat.math.ethz.ch
>[mailto:r-help-bounces at
2000 Jan 19
1
R for the Mac
Hello,
usually work with S-plus and/or with R, which I do prefer, on a Window
paltform.
Now I downloaded R for the Mac (I run it on a G4 at home) but I found
that many, too many functions are not available (svd, lm, glm and so
on... but still the lapply is missing...!).
I have ProFortran a C++ routine of my own but I can't pass them to that
version of R.
Is there anybody going to give a little
2010 Dec 20
2
How to optimize function parameters?
Hi,
I have a dataset and I want to fit a function to it.
The function is variogram model (http://en.wikipedia.org/wiki/Variogram)
The variogram model is defined by three parameters and I want them to be
automatically optimized for real time data.
I tried to use gafit {gafit} for this, but there are some data
configuration, where optimal results given by gafit() are negative, which is
not correct
2010 May 22
1
How to find all single minima, i.e. only each one within each next part of analyzed vector (table)
Dear R users,
How to find all single minima within each next part of analyzed vector (table)
Select all minima (mass_value=min & mass_value<2)
(many) in vector(table),
BUT first put mask on table in order to select
within one window mask (5 elements) only one local minimum, and next to search within
the next time window mask the second minimum (only one local along second mask)
2013 Mar 20
0
unexpected local minima/maxima with surf.gls
Hi there,
I use the surf.gls() function to fit a variable measured over a surface. When I plot the predicted surface, there are local minima/maxima in almost every coordinate where data were measured, which seems aberrant. For instance:
?? x <- c(343,293,343,243,293,343,443,543,593,243,293,343,393,443,493,543,593,143,193,243,293,343,393,443,
2005 Jun 15
1
Finding local minima and maxima
I have data in the form of (x,y) pairs and would like to find local
minima and maxima (typically the zeros of the 2nd derivative) of the y
values. I looked at numericDeriv, but I don't have an "expression" per
se. I looked at optim, also, but it looks like it will find only one
"global" max or min. I can code up my own piecewise derivatives, but
wondered if there is
2009 Nov 03
2
1 dimensional optimization with local minima
I am using numerical optimization to fit a 1 parameter model, in which the
input parameter is bounded. I am currently using optimize(), however, the
problem turns out to have local minima, and optimize does not always seem to
find the global minimum. I could to write a wrapping function that tries
multiple intervals or starting values, but I would prefer a package that has
built-in methods to make
2002 Mar 27
2
Error with nls
Dear R-group members,
I use:
platform i386-pc-mingw32
arch x86
os Win32
system x86, Win32
status
major 1
minor 4.1
year 2002
month 01
day 30
language R
I try to fit a 2 compartment model. The compartments are open, connected
to each other and
2011 May 25
0
approximate function and find local peaks (Maxima or Minima)
Hi,
I have a data-matrix:
> CB
Zeit Low
2 2011-05-02 08:05:05 7596.0
3 2011-05-02 08:10:06 7593.5
4 2011-05-02 08:15:11 7594.5
5 2011-05-02 08:20:15 7597.5
6 2011-05-02 08:25:18 7595.0
7 2011-05-02 08:30:20 7593.5
8 2011-05-02 08:35:21 7593.0
9 2011-05-02 08:40:21 7593.0
10 2011-05-02 08:45:25 7599.0
11 2011-05-02 08:50:34 7596.0
12
2005 Nov 11
1
optim not giving correct minima
Hello,
I am trying to use optim() on a function involving a summation. My
function basically is a thinned poisson likelihood. I have two parameters
and in most cases optim() does a fine job of getting the minima. I am
simulating my data based on pre specified parameters, so I know what I
should be getting. However when my true parameters fall in a particular
range, optim() gives
2001 Mar 10
2
Is availble CA, GA or MAS available for R for Win?
Hi.
Does anyone know whether CA(Cellular Automata), GA(Genetic Algorithm) or
Multi-Agent System is available for R for Win?
I've already knowna software for these areas, SWARM or startlogo.
But I'd like to link R's function with these methods.
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2005 Sep 23
2
Strange behaviour of as.Date function
Dear All,
I'm happily extracting data of temperature from an oracle db
under R via RODBC. After manipulating the extracted data I put them
into a data.frame 'dati' which is as follows:
> dati
DATA tm.
UDINE/RIVOLTO tm.TORINO/CASELLE
1 2005-07-01
22.35 23.80
2 2005-07-02 22.70
22.85
3 2005-07-03 23.80