Displaying 20 results from an estimated 1000 matches similar to: "Nonlinear Regression"
2003 Oct 30
2
'nls' and its arguments
Dear R experts!
I'd to fit data by 'nls' with me-supplied function 'fcn'.
1) I'd like 'fcn' to accept arbitrary arguments, i.e. I defined it
as f(...) {<body>}. (Ok, that's not actually impotant).
2) Second, I would NOT like to supply every parameter in the formula.
To illustrate this, let's look at the last example of 'nls' help
2010 Nov 10
1
par mfrow in "function" problem
Hi all,
I defined the following
#############################
myhist=function(x){
hist(x,xlab="",main="")
h=hist(x)
xfit=seq(min(x),max(x),length=100)
yfit=dnorm(xfit,mean(x),sd=sd(x))
yfit=yfit*diff(h$mids[1:2])*length(x)
lines(xfit, yfit, col="blue", lwd=2)
}
#############################
individually, it worked fine
however, if I used
par(mfrow=c(2,2))
2009 Sep 02
2
Howto fit normal curve into histogram using GGPLOT2
Currently, I am doing it this way.
x <- mtcars$mpg
h<-hist(x, breaks=10, col="red", xlab="Miles Per Gallon",
main="Histogram with Normal Curve")
xfit<-seq(min(x),max(x),length=40)
yfit<-dnorm(xfit,mean=mean(x),sd=sd(x))
yfit <- yfit*diff(h$mids[1:2])*length(x)
lines(xfit, yfit, col="blue", lwd=2)
But since, ggplot2 has more appealing
2005 Oct 14
1
lattice with predicted values
Dear lattice wizards,
I am trying to figure out how to plot predicted values in xyplot,
where the intercept, but not the slope, varies among conditioning
factor levels. I am sure it involves the groups, but I have been
unsuccessful in my search in Pinhiero and Bate, in the help files, or
in the archive, or in my attempts on my own.
My example follows:
FACT is a factor with levels a,b,c
2001 Oct 13
2
hist and normal curve
Dear R people:
I would like to superimpose a normal curve on a histogram.
I've seen this example in a book, somewhere.
I know that you draw the hist, get the mean and sd
of the data set, but then I'm stuck.
Could you help, please?
Thanks!
Erin
hodgess at uhddx01.dt.uh.edu
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2010 Feb 19
1
"Legend" question
Hi,
I want to get a histogram with the legend for my data. I drew a normal density curve and kernel density curve in the histogram, and I also label mean and median in the X axis. From the code, I got two legend: One shows "Normal Density" and "Kernel Density" and their corresponding lines, the other shows "Mean = value" and "Median = value" and their
2005 Sep 25
4
hist(x, ...) with normal distribution curve
.
I am looking for a histogram or box plot with the adding normal
distribution curve
I think that must be possible, but I am not able to find out how to do.
Regards Knut
2004 May 21
1
Buglet/omission in nls package (PR#6901)
Dear all,
I noticed the following under R 1.8.1 (when nls was still a separate
package) but the same problem occurs under R 1.9.0 (where most (all?)
of nls is now in the stats package):
> data(Puromycin)
> fm <- nls(rate~SSmicmen(conc,b0,b1), Puromycin, subset = state=="treated")
> coef(summary(fm))
NULL
The problem seems to be that summary.nls uses the name
2006 Jul 18
4
How can I extract information from list which class is nls
Hello!
I work with :
R : Copyright 2006, The R Foundation for
Statistical Computing
Version 2.3.1 (2006-06-01)
On Windows XP Professional (Version 2002) SP2.
At this moment I use the function "nls" combined
with a selfStar model (SSmicmen, related to
Michaelis-Menten equation, and provided by the
"stats" package).
When I realise the following operation (cf. p 59
of the
2004 Nov 08
2
Nonlinear weighted least squares estimation
Hi there,
I'm trying to fit a growth curve to some data and need to use a weighted least squares estimator to account for heteroscedasticity in the data. A weights argument is available in nls that would appear to be appropriate for this purpose, but it is listed as 'not yet implemented'. Is there another package which could implement this procedure?
Regards,
Robert Brown
2000 Nov 09
2
simple mixture
Dear All,
I am trying to do some simple mixture analyses. For instance, I have a
sample of n observations and I suspect they come from two different
exponential distributions with parameters rate1 and rate2, respectively.
So, I want to estimate rate1, rate2, and the proportions of both kinds of
individuals in the sample. I had a look at the packages mda and mclust, but
they do not seem to do this
2005 Jul 11
2
Weighted nls
Dear R Community,
I am attempting to perform a weighted non-linear least squares fit. It has already been noted that the weights option is not yet implemented for the nls function, but no one seems to offer any suggestions for getting around this problem. I am still curious if a) anyone has code they have written which includes a weight options for nls, or b) if there is another model which
2004 Feb 02
1
Robust nonlinear regression - sin(x)/x?
You reall have only one parameter in your model, c = a/b. You can't
identify both a and b from your model, therefore, you should fit the
linear model: lm(z ~ c* sin(x)/x)
Ravi.
----- Original Message -----
From: cstrato <cstrato at aon.at>
Date: Monday, February 2, 2004 2:28 pm
Subject: [R] Robust nonlinear regression - sin(x)/x?
> Dear all
>
> Since I did not receive any
2005 Oct 14
2
Help with lattice, regressions and respective lines
# Dear R list,
#
# I'm needing help with lattice, regression and respective lines.
# My data is below:
bra = gl(2, 24, label = c('c', 's'))
em = rep(gl(3, 8, label = c('po', 'pov', 'ce')), 2)
tem = rep(c(0, 0, 30, 30, 60, 60, 90, 90), 6)
tem2 = tem^2
r = rep(1:2, 24)
y = c(40.58, 44.85, 32.55, 35.68, 64.86, 51.95, 42.52, 52.21,
2005 Aug 12
6
evaluating string variables
Hello!!!
I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)
#define data frame
L <- data.frame(frame=numeric(7),
2006 Nov 29
3
R2.4 xyplot + panel.number problem
Hi all;
I'm trying to display a 2 panel plot for the Puromycin data from R
with 2 different non-linear models fitted to each group. The problem
is that as far as I know panel.number doesn't work in the latest
version of R. Can anyone give a hint how to solve this?
Here is the code that I used before and now doesn't work
xyplot(rate ~conc| state,Puromycin,
2006 Apr 18
1
Nonlinear Regression model: Diagnostics
Hi,
I am trying to run the following nonlinear regression model.
> nreg <- nls(y ~ exp(-b*x), data = mydf, start = list(b = 0), alg = "default", trace = TRUE)
OUTPUT:
24619327 : 0
24593178 : 0.0001166910
24555219 : 0.0005019005
24521810 : 0.001341571
24500774 : 0.002705402
24490713 : 0.004401078
24486658 : 0.00607728
24485115 : 0.007484372
2011 Apr 20
1
How can I 'predict' from an nls model with a fit specified for separate groups?
Following an example on p 111 in 'Nonlinear Regression with R' by Ritz &
Streibig, I have been fitting nls models using square brackets with the
grouping variable inside. In their book is this example, in which
'state' is a factor indicating whether a treatment has been used or not:
> Puromycin.m1 <- nls(rate ~ Vm[state] *
+ conc/(K[state] + conc), data = Puromycin,
2003 Oct 28
2
Confidence ellipse for correlation
Hello,
SAS' point and click interface has the option of produce a scatterplot with a
superimposed confidence ellipse for the correlation coefficient. Since I
generally like R so much better, I would like to reproduce this in R. I've
been playing with the ellipse package. In order to have the points and the
ellipse on the same graph I've done the following.
(Load ellipse
2004 Feb 04
1
Fitting nonlinear (quantile) models to linear data.
Hello.
I am trying to fit an asymptotic relationship (nonlinear) to some
ecological data, and am having problems. I am interested in the upper
bound on the data (i.e. if there is an upper limit to 'y' across a range
of 'x'). As such, I am using the nonlinear quantile regression package
(nlrq) to fit a michaelis mention type model.
The errors I get (which are dependant on