Displaying 20 results from an estimated 7000 matches similar to: "nlmin"
1999 Jan 21
2
nlm question
Hello again
Is there any way (or an alternative non-linear minimiser) that arguments
to the function called in nlm can be passed in version 0.62.4? Like (I
believe) nlmin in a well known other program or optimise in R. Do we use
global variables? Shurely not!
\John
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r-help mailing list -- Read
1999 Dec 03
1
R-help Digest V1 #34
R-help Digest Friday, December 3 1999 Volume 01 : Number 034
In this issue:
[R] model.tables
Re: [R] Installing R on Slackware Linux
Re: [R] Installing R on Slackware Linux
[R] nlmin
Re: [R] nlmin
Re: [R] nlmin
Re: Summary: [R] Wanted: online Introduction to R
[R] Applying a function of several variables to data
Re: [R] R and XML -- a near perfect
2003 Sep 04
3
function is too long to keep source
Dear R users,
I am trying to minimise a function using "nlm".
I am getting the following error message: "Error: function is too long to
keep source"
The function is really very long (about 100 A4 pages).
Is there anything I could do to solve this problem?
At the moment I am using "nlmin" in S-Plus with no problems but I'd prefer
to use R.
Thank you very
2008 Apr 22
2
optimization and gradient
Dear all,
I am using the functions 'optim' and 'nlminb'. For both, you can provide
a function which computes the gradient of the objective function (to
enhance speed and precision). In my case, both the objective function
and the gradient take time to be computed and share many common
computations (similar matrix, products, etc...). Therefore, I have to
compute these
2009 Mar 25
1
intelligent optimizer (with domain restrictions?)
dear R experts---sorry, second question of the day. I want to match some
moments. I am writing my own code---I have exactly as many moment
conditions as parameters, and I am leary of having to learn the magic of
GMM weighting matrices (if I was to introduce more). the process sounds
easy conceptually. (Seen it in seminars many times, so how hard could it
possibly be?...me thinks) first
2010 Feb 02
1
how to use optim() or nlm() to solve three nonlinear equations
Dear all,
I just know how to solve an eaquation by using optim() or nlm(). But, now, I have three nonlinear equations,
how could we use optim() or nlm() to solve a system of nonlinear equations in R? Thank you so much.
Sincerely,
Joe
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2005 Dec 04
1
Understanding nonlinear optimization and Rosenbrock's banana valley function?
GENERAL REFERENCE ON NONLINEAR OPTIMIZATION?
What are your favorite references on nonlinear optimization? I like
Bates and Watts (1988) Nonlinear Regression Analysis and Its
Applications (Wiley), especially for its key insights regarding
parameter effects vs. intrinsic curvature. Before I spent time and
money on several of the refences cited on the help pages for "optim",
2005 Aug 25
2
concerning econometrics usage of "R"
Hi,
I am currently looking for a program or programmng language easy to
learn, easier to operate on.I heva heard about "R", However I
understand that "R" is designed especially for statisticians. As an
economist, working on applied econometrics, I am not sure if it can
meet my needs.
Will I be able to reach precise time series or panal data regression
results with
2009 Apr 20
1
Two or more dimensional root (Zero) finding
Good morning to all,
I should find the zero of a specific function with
respect to a vector of arguments.
Does it exist something similar in R?
Thank
you very much,
Enrico Foscolo
2004 Oct 12
2
constrained optimization using nlm/optim?
I'm looking for an example of a simple R script that impliments a
contrained nonlinear function using nlm or optim. I'm not exactly sure how
to impliment the constraints within the objective function that is passed
to nlm/optim.
obj.func <- function( p ) {
x(p) <- unconstrained obj function value
if( constraint1 > something ) {
obj.func <- x(p)
} else {
1998 Mar 12
2
R-beta: nonlinear fitting
Thanks very much Douglas for the pointer to nlm.
Maybe the "Notes on R" maintainer can add at least a mention of nlm in the
section on nonlinear fitting?
I never did nonlinear fitting in S-Plus before, so I have nothing to
unlearn, but I was hoping someone could show me how to do a least squares
fit with nlm.
example:
x<-c(1,2,3,4,5,6)
y<-.3*x^-.6 +.2
y<-y+rnorm(6,0,.01)
1998 Mar 12
2
R-beta: nonlinear fitting
Thanks very much Douglas for the pointer to nlm.
Maybe the "Notes on R" maintainer can add at least a mention of nlm in the
section on nonlinear fitting?
I never did nonlinear fitting in S-Plus before, so I have nothing to
unlearn, but I was hoping someone could show me how to do a least squares
fit with nlm.
example:
x<-c(1,2,3,4,5,6)
y<-.3*x^-.6 +.2
y<-y+rnorm(6,0,.01)
2001 Apr 27
3
nls question
I have a question about passing arguments to the function f that nlm
minimizes.
I have no problems if I do this:
x<-seq(0,1,.1)
y<-1.1*x + (1-1.1) + rnorm(length(x),0,.1)
fn<-function(p)
{
yhat<-p*x+(1-p)
sum((y-yhat)^2)
}
out<-nlm(fn,p=1.5,hessian=TRUE)
But I would like to define
fn<-function(x,y,p)
{
yhat<-p*x+(1-p)
sum((y-yhat)^2)
}
so
2011 Mar 11
2
Ifs in formula
Dear r-helpers,
This might be an elementary question, but I have a hard time getting
my head around it, so all help is much appreciated.
I am working on a nonlinear regression model of the form
if z > 0
y = f1(x,y),
else
y = f2(x,t) .
In other words, the functional form of f(.) changes according to some
criteria z. Natural approach would be to fit two models, i.e.
model1 <- nlm(y ~ ...,
1998 Apr 14
1
R-beta: SEs for one-param MLE in R?
Simple-mindedly I tried getting MLE and SE for one-parameter model in the
same way as for multi-param models.
out<-nlm(fn,p=c(2),hessian=T)
But
sqrt(diag(solve(out$hessian)))
gives the answer 1. The Hessian has only one entry, not really a matrix.
diag(x) gives 1 if x is just a single number.
Is this what I should be doing to get SE for MLE?
sqrt(solve(out$hessian))
Thanks very much for
1998 Apr 14
1
R-beta: SEs for one-param MLE in R?
Simple-mindedly I tried getting MLE and SE for one-parameter model in the
same way as for multi-param models.
out<-nlm(fn,p=c(2),hessian=T)
But
sqrt(diag(solve(out$hessian)))
gives the answer 1. The Hessian has only one entry, not really a matrix.
diag(x) gives 1 if x is just a single number.
Is this what I should be doing to get SE for MLE?
sqrt(solve(out$hessian))
Thanks very much for
2004 Feb 24
5
Nonlinear Optimization
Hi,
I have been brought back to the "R-Side" from MatLab. I have used R in
graduate econometrics but only for statistics and regression (linear and
nonlinear). But now I need to run general nonlinear optimization.
I know about the add-in quadprog but my problem is not QP. My problem is a
general nonlinear (obj funct) with linear constraints.I know about the "ms"
and
2013 Jan 12
2
Getting the R squared value in asymptotic regression model
Please help getting the R squared value in asymptotic regression model
I use the code below
model1<-nls(GN1~SSasymp (nrate,a,b,c), data = data.1 )
and R produced the modell coefficients without the R squared value?
--
Ahmed M. Attia
Research Assistant
Dept. Of Soil&Crop Sciences
Texas A&M University
ahmed <ahmedatia@zu.edu.eg>.attia@ag.tamu.edu
Cell phone:
2008 Aug 05
1
optimize simultaneously two binomials inequalities using nlm( ) or optim( )
Dear R users,
I?m trying to optimize simultaneously two binomials inequalities (used in
acceptance sampling) which are nonlinear solution, so there is no simple
direct solution. Please, let me explain shortly the the problem and the
question as following.
The objective is to obtain the smallest value of 'n' (sample size)
satisfying both inequalities:
(1-alpha) <= pbinom(c, n, p1)
2004 Aug 25
3
Beginners Question: Make nlm work
Hello,
I'm new to this and am trying to teach myself some R by plotting
biological data. The growth curve in question is supposed to be fitted
to the Verhulst equation, which may be transcribed as follows:
f(x)=a/(1+((a-0.008)/0.008)*exp(-(b*x)))
- for a known population density (0.008) at t(0).
I am trying to rework the example from "An Introduction to R" (p. 72)
for my case and