Displaying 20 results from an estimated 9000 matches similar to: "Code/doc inconsistancy in constrOptim (PR#7346)"
2009 Nov 02
2
a prolem with constrOptim
Hi,
I apologize for the long message but the problem I encountered can't be stated in a few lines.
I am having some problems with the function constrOptim. My goal is to maximize the likelihood of product of K multinomials, each with four catagories under linear constraints on the parameter values. I have found that the function does not work for many data configurations.
#The likelihood
2009 Nov 18
1
bug in '...' of constrOptim (PR#14071)
Dear all,
There appears to be a bug in how constrOptim handles ... arguments that
are suppose to be passed to optim, according to the documentation. This
means you can't get the hessian to be returned, for example (so this is
a real problem, and not just a question of mistaken documentation).
Looking at the code, it appears that a call to the user-defined f
includes the ..., when the ...
2003 Oct 29
1
constrOptim doesn´t send arguments to optim!(?)
Hi,
I think that there something wrong with the 'constrOptim' max/minimization
function because she doesn?t send extra arguments to 'optim' call.
Fact: When I use optim in a f(x,theta)-like function, everything goes ok.
But using constrOptim with the same function leads to error...
Proof: Make a small change in the 'Rosenbrock Banana function' (taken from
the Examples
2010 Jun 17
2
constrOptim( ): conflict between help page and code
There is a contradiction between what the help page says and what constrOptim actually
does with the constraints. The issue is what happens on the boundary.
The help page says
The feasible region is defined by ?ui %*% theta - ci >= 0?,
but the R code for constrOptim reads
if (any(ui %*% theta - ci <= 0))
stop("initial value not feasible")
The following example
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 Jul 14
2
constrOptim and function with additional parameters?
How can I use a function with some additional input parameters
in constrOptim? For example, something like
fr <- function(x,a) { ## Rosenbrock Banana function
x1 <- x[1]
x2 <- x[2]
a * (x2 - x1 * x1)^2 + (1 - x1)^2
}
where the optimum is to be found w.r.t. x. Calling
optim(c(-1.2,1), fr, NULL, a=100) works as expected, but I fail
to provide the a=100 in the constrained case:
2009 Jun 03
1
Using constrOptim() function
I have a function myFunction(beta,x) where beta is a vector of coefficients
and x is a data frame (think of it as a matrix). I want to optimize the
function myFunction() by ONLY changing beta, i.e. x stays constant, with 4
constraints. I have the following code (with a separate source file for the
function):
rm(list=ls())
source('mySourceFile')
2011 Dec 21
1
constrOptim and further arguments
Dear List,
I have the code below, where I am using the constrained optimisation
package, 'constrOptim.nl' to find the values of two values, b0 and b1.
I have no problems when I enter further variable information DIRECTLY into
the functions, fn, and heq. In this instance I require fn to have -0.0075
appended to it, and in the case of heq, h[1] has -0.2.
library(alabama)
2008 May 12
1
hessian in constrained optimization (constrOptim)
Dear helpers,
I am using the function "constrOptim" to estimate a model with ML with an
inequality constraint using the option method='Nelder-Mead'.
When I specify the option: hessian = TRUE I obtain the response:
Error in f(theta, ...) : unused argument(s) (hessian = TRUE)
I guess the function "constrOptim" does not allow this argument which, on
the other hand, is
2007 Sep 07
1
'initial value not feasible' in constrOptim
Dear friends.
I am using function
constrOptim(c(0.5,0.3,0.5), fit.error, fit.error.grr, ui=-1*ui,ci=-1*ci)
and I am confronted with error message "initial value not feasible"
I plug in the initial value of (0.5,0.3,0.5) to function fit.error and
fit.error.grr and have pretty reasonable result. I inequality "ui %*% theta
- ci >= 0" as suggested in the R manual and it is
2010 Apr 28
1
Problem with optimization (constrOptim)
Hello,
I have the following problem:
I have a set of n matrix equations in the form of :
[b1] = [A] * [b0]
[b2] = [A] * [b1]
etc.
vertical vectors [b0], [b1], ... are GIVEN. We try to estimate matrix A. As
there are many equations (more than cells in matrix A) the system has no
solutions.
A is transition matrix (stochastic matrix) or markov process, so the sum of
each row = 1 and each entry is
2005 Sep 26
2
constrOptim (PR#8158)
Full_Name: Haobo Ren
Version: 2.1.1
OS: Windows 2000
Submission from: (NULL) (192.11.226.116)
When running constrOptim, there is error message
Error: subscript out of bounds
2008 Jun 08
2
optim, constrOptim: setting some parameters equal to each other
Hello, and apologies for the upcoming naive questions. I am a biologist who is trying to teach himself the appropriate areas of math and stats. I welcome pointers to suggested background reading just as much as I do direct answers to my question.
Let's say I have a function F() that takes variables (a,b,c,a1,b1,c1) and returns x, and I want to find the values of these variables that result in
2009 Apr 23
6
Stuck using constrOptim
Trying to use constrOptim to minimize the sum of squared deviations. I put
the objective function in as: sum((x %*% Y - Z)^2) so i'm trying to get
values for x to minimize the sum of the squared deviations between the
product of x and Y and Z.
Anyways i have no problem using this when x is a 3x1 test variable. it
works great with the constraints and everything. when i actually use it on
2006 Feb 01
1
output hessian matrix in constrOptim
Hi,
Is there any way to get the hessian matrix from the "constrOptim" function without supplying gradient function? Thanks.
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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
2012 Sep 17
2
Constraint Optimization with constrOptim
Hi,
I am having trouble using constrOptim. My target is to do a portfolio optimization and there some constraints have to be fulfilled.
1) The weight of each share of the portfolio has to be greater than 0
2) The sum of these weights has to be 1
I am able to fulfill either the first or the second constraint but not both.
One simple way would be to fulfill the first constraint by using optim as
2013 Feb 09
1
Optimization Problem in R
Dear List,
I'm new in R. I'm trying to solve a simple constrained optimization
problem.
Essentially, let's say I have a matrix as in the object 'mm' inside the
function below. My objective function should have a matrix of parameters,
one parameter for each element 'mm' (4 in this case). The problem is to
select the value of the parameters to maximize the function
2007 Sep 10
2
Are the error messages of ConstrOptim() consisten with each other?
Dear Friends.
I found something very puzzling with constOptim(). When I change the
parameters for ConstrOptim, the error messages do not seem to be
consistent with each other:
> constrOptim(c(0.5,0.3,0.5), f=fit.error, gr=fit.error.grr, ui=ui,ci=ci)
Error in constrOptim(c(0.5, 0.3, 0.5), f = fit.error, gr = fit.error.grr, :
initial value not feasible
> constrOptim(c(0.5,0.9,0.5),
2003 Oct 31
1
help with constrOptim function
Hello. I had previously posted a question concerning the optimization
of a nonlinear function conditional on equality constraints. I was
pointed towards the contrOptim function. However, I do not understand
the syntax of this function with respect to specifying the constraints
and so I don’t know if it is what I need. The command is:
constrOptim(theta, f, grad,ui,ci,…). “theta” is the