Displaying 20 results from an estimated 1000 matches similar to: "Optimization with constraint."
2008 Mar 26
1
Optimization with nonlinear constraints
Hello.
I have some further problems with modelling an
optimization problem in R:
How can I model some optimization problem in R with a
linear objective function with subject to some
nonlinear constraints?
I would like to use "optim" or "constrOptim", maybe
with respect to methods like "Simulated Annealing" or
"Sequential Quadric Programming" or something
2008 Jun 26
1
Question about Constraint Optimization
Dear All,
I am having trouble in using R function "constrOptim" to do constraint
optimization. It seems that "constrOptim" calls function "optim" when it
does the optimization, and "optim" allows us to set "method" to be "SANN"
if we want to use simulated annealing. In "optim", the function allows us
to set gradient to be
2008 Jan 18
1
constrOptim with method SANN
Hi Everyone,
I'm trying to minimize a function using constrOptim with
the simulated annealing method SANN.
If I understand constrOptim well, it basically passes most
of its arguments to optim while somehow enforcing the constraints.
My problem is, that since SANN does not need gradients,
when using optim with SANN, the gr argument of optim is
used to specify a function to create the next
2007 Aug 02
1
constraint in constrOptim
I'm using the function constrOptim together with the "SANN" method and
my objective function (f) has two parameters. One of the parameters
needs be into (2^(-10), 2^4) range and the other into (2^(-2), 2^12)
range. How can I do it using constrOptim??
Thank you
André Rossi
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2010 Sep 17
1
Nonlinear programming problem
Hello useRs,
I'm using the command "solnp" in package "Rsolnp" to solve a general nonlinear programming problem. But I got an error that " the leading minor of order 15 is not positive definite
". Can anybody tell what may cause this error? Does it have something to do with the starting values?
Thanks a lot!!!
Xiaoxi
[[alternative HTML version
2008 Jan 18
0
constrOptim with SANN
Hi Everyone,
I'm trying to minimize a function using constrOptim with
the simulated annealing method SANN.
If I understand constrOptim well, it basically passes most
of its arguments to optim while somehow enforcing the constraints.
My problem is, that since SANN does not need gradients,
when using optim with SANN, the gr argument of optim is
used to specify a function to create the next
2008 Oct 02
0
Comments for squeue.c; part 2.
1.
566 squeue_enter(squeue_t *sqp, mblk_t *mp, mblk_t *tail, uint32_t cnt,
Why cnt is declared as uint32_t (fixed size?) Why not just int or uint_t?
554 * squeue_enter() - enter squeue sqp with mblk mp (which can be
555 * a chain), while tail points to the end and cnt in number of
556 * mblks in the chain.
It is not quite clear what is a tail (and why it is needed as well)
558 * For
2010 Jul 07
4
constrained optimization
Dear list,
The task view on optimization does not reference a package for non linear
constrained optimization problems. Stefan Theussl told me to look at the
Rsolnp package, but unfortunately it is not very clear what method is R
ported. (The authors ported the matlab code of Yinyu Ye
http://www.stanford.edu/~yyye/ <http://www.stanford.edu/%7Eyyye/>)
Currently I'm looking for an
2006 Feb 28
3
any more direct-search optimization method in R
Hello list,
I am dealing with a noisy function (gradient,hessian not available) with
simple boundary constraints (x_i>0). I've tried constrOptim() using nelder
mead to minimize it but it is way too slow and the returned results are not
satisfying. simulated annealing is so hard to tune and it always crashes R
program in my case. I wonder if there are any packages or functions can do
2011 Sep 08
3
global optimisation with inequality constraints
Dear All,
I would like to minimise a nonlinear function subject to linear inequality constraints as part of an R program. I have been using the constrOptim function. I have tried all of the methods that come with Optim, but nothing finds the correct solution. If I use the correct solution as the vector of starting values, though, my program does output the correct solution and optimum - the
2006 Sep 02
1
nonlinear least squares fitting Trust-Region"
Dear Mr Graves,
Thank you very much for your response. Nobody else from this mailing list ventured to reply to me for the two weeks since I posted my question.
"nlminb" and "optim" are just optimization procedures. What I need is not just optimization, but a nonlinear CURVE FITTING procedure. If there is some way to perform nonlinear curve fitting with the
2012 Dec 07
1
Error using constrOptim in constraint definition
Hello,
I'm trying to run constrOptim. It returns to me an error about the fact that constraints arguments (ui and ci) are non compatibles:
> optout= constrOptim(startparams, f=ImpulseSS, grad=grImpulse, ui=UI, ci=CI, data=gexp[k,], t=t)
Error in ui %*% theta : non-conformable arguments
I would like to point out that I can calculate that product in the command line:
> UI %*%
2004 Aug 09
4
linear constraint optim with bounds/reparametrization
Hello All,
I would like to optimize a (log-)likelihood function subject to a number of
linear constraints between parameters. These constraints are equality
constraints of the form A%*%theta=c, ie (1,1) %*% 0.8,0.2)^t = 1 meaning
that these parameters should sum to one. Moreover, there are bounds on the
individual parameters, in most cases that I am considering parameters are
bound between zero
2005 Dec 13
0
Constrained Log-Likelihood with SQP Solver
Dear R-Users,
I'm searching for somebody who can support me or even likes to
collaborate with
me in setting up an R-package for "constrained maximim log-likelihood"
parameter
estimation.
For example fitting the parameters of a MA(1)-APARCH(1,1) model for a
time series
of 17'000 points (e.g. the famous Ding-Granger-Engle mode) takes about
10 minutes
with the existing
2006 Oct 20
1
Cardinality constraint
Hello,
How do I implement a cardinality constraint with constrOptim?
I want to minimize (least square) a%*%x = 4
subject to
x1<2
x2<1
x3<4
count(x1, x2, x3)= 2 (cardinality constraint)
Is there a way to specify binary integer variables with constrOptim?
Here's my code so far:
a <-matrix(1:3,1,3)
fr <- function(x) {
(a%*%x-4)^2
}
2004 Oct 02
1
constraints in optim?
>
optim(c(1,1),LL,method="SANN",control=list(fnscale=-1),trans=trans,times=times)
$par
[1] 17.422635 -1.606859
How could i constraint that the parameters should be both positive in
my maximizing problem?
I check constrOptim but here i could only constraint the variables trans and
times and not my parameters?
many thanks, regards
Christian
2010 Dec 06
1
How to formulate constraint like abs(x) = y in constrOptim (or other)
Hello list reader,
I am trying to form some constraints for an optimization I am working on.
I think I have understand the use of the constraints in matrix form. I use
them like:
constr_mat<- -diag(2)
constr_vec<- rep(-0.05,2)
constr_mat<- rbind(constr_mat, diag(2))
constr_vec<- c(constr_vec, rep(-1, 2))
To get parameters in the interval [-1, 0.05]. (And this works so far)
Now I
2009 Nov 04
3
Constrained Optimization
Hi All,
I'm trying to do the following constrained optimization example.
Maximize x1*(1-x1) + x2*(1-x2) + x3*(1-x3)
s.t. x1 + x2 + x3 = 1
x1 >= 0 and x1 <= 1
x2 >= 0 and x2 <= 1
x3 >= 0 and x3 <= 1
which are the constraints.
I'm expecting the answer x1=x2=x3 = 1/3.
I tried the "constrOptim" function in R and I'm running into some issues.
I first start off
2011 Oct 31
2
Linear Regression with Linear Equality Constraint
Please advice on the package I should use to run a linear regression model
(weighted least squared) with linear equality constraint. I initially tried
"constrOptim" but it turned out that it only supported inequality linear
constraint. Thank you very much in advance.
Cheers,
Jon
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2006 Oct 06
1
Relative constraint using constrOptim?
I am trying to optimize a likelihood function using constrOptim. I
know from prior research that, e.g. x1>x2. Is there a way to include
that constraint into the optimization routine, i.e. the ci
constraint? The examples I found only use absolute numeric values for
the constraint and not relative values. My attempts to include it
into ci failed: e.g. ci=c(1, x[1]).
Am I using the