these data?
thanks for the help
Am 27.09.2012 21:27, schrieb Berend Hasselman:
y_val<-115-118*exp(-0.12*(seq(1,100)+rnorm(100,0,0.8)))
>x_val<-seq(1:100)
>plot(y_val~x_val)
>summary(mod1<-nls(y_val~a-b*exp(-c*x_val),start=list(a=115,b=118,c=0.12)))
>
--
Benedikt G
line does about as
well as anything except for the 3 high leverage points, which the
minimization is probably having trouble with.
-- Bert
On Thu, Sep 27, 2012 at 10:43 AM, Benedikt Gehr
wrote:
quantiles<-c(seq(.05,.95,0.05))
slopes<-c( 0.00e+00, 1.622074e-04 , 3.103918e-03 , 2.
l the values it doesn't work
any longer.
Then I simulated perfect asymptotic decay data and tried to to fit an
nls() with the correct parameter values, but it won't work either. What
am I doing wrong?
Any help would be most appreciated
Best
benedikt
--
Benedikt Gehr
Ph.D. Student
I
> Sent from my iPad
>
> On May 16, 2012, at 3:27, Benedikt Gehr <[hidden email]
> > wrote:
>
> > Hi
> >
> > I have a rather large data frame (>7000 rows with 28 columns) which
> I want
> > to sort by date. Below I have a example of the data frame
Hi
I have a rather large data frame (>7000 rows with 28 columns) which I want
to sort by date. Below I have a example of the data frame. The Date column
is called DT, is a factor and looks like this:
class(res.merge$DT)
[1] "factor"
head(res.merge$DT)
[1] 17.3.2012 13:54:02 17.3.2012 14:00:07 17.
Hi
I am fitting an arima model to some time series X. When I was comparing
the fitted values of the model to the true time series I realized that
the true time series lags one time step behind the fitted values of the
arima model. And this is the case for any model. When I did a simple
linear
Hi
I posted this problem yesterday but didn't get a reply so I try again today.
I hope someone can help me with this.
thank you very much for the help
cheers
Benedikt
I would like to use arima () to find the best arima model for a time
series. The default in arima appar
Hi
I would like to use arima () to find the best arima model for y time
series. The default in arima apparently is to use conditional sum of
squares to find the starting values and then ML (as described on the
help page).
Now using the default may lead to error messages saying: "non-stationary
Hi
I'm trying to fit arima models with the arima() function and I have two
questions.
##
##1. ##
##
I have n observations for my time series. Now, no matter what
arima(p,d,q)- model I fit, I always get n residuals. How is that possible?
For example: If I try this out myself on an AR(
Hi
I think my first answer doesn't seem to have gone through due to the
attachement. So I copy pasted my last answer including the code below.
Sorry about that:
Hi Paul
Oh ok sorry, I send you below a copy of the R code I was using. It's very
possible that my programmi
Hi Paul
Oh ok sorry, I send you below a copy of the R code I was using. It's very
possible that my programming is slow as well. I'm very happy to learn.
Sorry the code is a bit long, but its structured like this and cotains three
main functions and the optimization:
1. Input
Hi
I implemented the age-structure model in Gove et al (2002) in R, which is a
nonlinear statistical model. However running the model in R was very slow.
So Dave Fournier suggested to use the AD Model Builder Software package and
helped me implement the model there.
ADMB was incr
Hi
I'm trying to read a data file with output from another program (admb)
into R for further analysis. However I'm not very successfull. The file
extension for the data file is file.rep but it also doesn't help when I
change it to file.txt
I have two problems/questions:
1. The file is a sin
Hi
I'm trying to run an admb model from R by using the system () command.
The admb model runs fine when running it from the admb command line or
when using emacs. However when I try it with system() then R crashes
every time.
And I tried using the R command line and RGui and in both it crashes
Hi
I'm using mle2 for optimization of a multinomial likelihood. The model fit
is not very good and I would like to look at the likelihood profiles.
However I'm optimizing many parameters (~40) so using the function profile()
takes forever and is not practical. How can I calculate approximate
Hi
I'm trying to maximize a joint likelihood of 2 likelihoods (Likelihood 1 and
Likelihood 2) in mle2, where the parameters I estimate in Likelihood 2 go
into the likelihood 1. In Likelihood 1 I estimate the vector logN with
length 37, and for the Likelihood 2 I measure a vector s of length 8.
numbers vs expected from the
model",xlim=c(0,200),ylim=c(0,200))
abline(0,1)
##
##Plots
##
##Plot true population trend <-> compare with estimated trend
plot(rowSums(N.true)~seq(1:y),ylim=c(0,5000),col="red",pch=17,main="True vs
estimated population trend")
lines(rowSums(N.true)~seq(1:y),col="red")
points(rowSums(Nya)~seq(1:y),ylim=c(0,5000),col=&quo
Hi there
I am using mle2 for a multinomial likelihood optimization problem. My
function works fine when I'm using simulated data, however my cell
probabilities of the true data for the multinomial likelihood are
sometimes very small (in some cases <0.00...) and the estimated point
estimates f
hi
I'm trying to use the function odiag(x) for matrix calculations. I would
like to assign new values to an off-diagonal in a matrix.
When I use the diag (x) function I could write something like
p<-matrix(seq(1:12),ncol=4)
p.new<-matrix(rep(0,12),ncol=4)
diag(p.new)<-diag(p)
p.new
But this w
Hi there
I'm trying to find the mle fo a multinomial model ->*L(N,h,S¦x)*. There
is only *N* I want to estimate, which is used in the number of successes
for the last cell probability. These successes are given by:
p^(N-x1-x2-...xi)
All the other parameters (i.e. h and S) I know from somewhere
Hi there
I am trying to learn how to compute mle in R for a multinomial negative
log likelihood function.
I am using for this the book by B. Bolker "Ecological models and data in
R", chapter 6: "Likelihood an all that". But he has no example for
multinomial functions.
What I did is the follo
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