Displaying 20 results from an estimated 4000 matches similar to: "intelligent optimizer (with domain restrictions?)"
2009 Aug 07
1
Gauss-Laguerre using statmod
I believe this may be more related to analysis than it is to R, per se.
Suppose I have the following function that I wish to integrate:
ff <- function(x) pnorm((x - m)/sigma) * dnorm(x, observed, sigma)
Then, given the parameters:
mu <- 300
sigma <- 50
m <- 250
target <- 200
sigma_i <- 50
I can use the function integrate as:
> integrate(ff, lower= -Inf, upper=target)
2006 Feb 10
1
Lmer with weights
Hello!
I would like to use lmer() to fit data, which are some estimates and
their standard errors i.e kind of a "meta" analysis. I wonder if weights
argument is the right one to use to include uncertainty (standard
errors) of "data" into the model. I would like to use lmer(), since I
would like to have a "freedom" in modeling, if this is at all possible.
For
2010 Aug 02
2
Dealing with a lot of parameters in a function
Hi all,
I'm trying to define and log-likelihood function to work with MLE.
There will be parameters like mu_i, sigma_i, tau_i, ro_i, for i between
1 to 24. Instead of listing all the parameters, one by one in the
function definition, is there a neat way to do it in R ? The example is
as follows:
ll<- function(mu1=-0.5,b=1.2,tau_1=0.5,sigma_1=0.5,ro_1=0.7)
{ if (tau1>0 &&
2017 Jun 12
2
Possible with enableJIT function
In this email to the R-help list: https://stat.ethz.ch/pipermail/r-help/2017-June/447474.html
and in this question on Stackoverflow: https://stackoverflow.com/questions/44486643/nleqslv-memory-use-in-r
Andrew Leach has raised a question about the memory usage of my package nleqslv.
In a model with a loop within a function he has experienced continuously increasing memory usage
by package nleqslv
2012 Mar 20
2
SE from nleqslv
Dear R-users,
I use the "nleqslv" function to get parameter estimates by solving a system
of non-linear equations. But I also need standard error for each of
estimates. I checked the nleqslv manual but it didn't mention about SE.
Is there any way to get the SE for each estimate?
Thank you very much.
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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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2017 Aug 10
1
"Help On optim"
Hello,
I have some parameters from Mclust function. The parameters are in the form
*parametersDf *
* mu_1 mu_2 var_mc1 var_mc2 c1
c2 *
*2 1.357283 2.962736 0.466154 0.1320129 0.5258975
0.4741025 *
*21 8.357283 9.962736 0.466154 0.1320129 0.5258975
0.4741025 *
Each row in the above data frame
2014 Aug 25
3
dubious behaviour of match.arg() with nested functions.
Dear all,
I initially ran into this problem while rebuilding a package dependent on
nleqslv. I got the following error:
Error in match.arg(global) : 'arg' must be of length 1
This didn't occur in previous versions of nleqslv, but did in the current
one (2.4). I think I pinned the problem down to the following example:
Take two functions:
test <-
2010 Jul 29
7
newton.method
Hi,
Is this method broken in R? I am using it to find roots of the following
function:
f(x) = 2.5*exp(-0.5*(2*0.045 - x)) + 2.5*exp(-0.045) + 2.5*exp(-1.5*x) - 100
It is giving an answer of -38.4762403 which is not even close (f(x) =
2.903809e+25 for x=-38.4762403). The answer should be around 0.01-0.1. This
function should converge..
Even for a simple function like f(x) = exp(-x) * x, it gives
2011 Nov 12
1
State space model
Hi,
I'm trying to estimate the parameters of a state space model of the
following form
measurement eq:
z_t = a + b*y_t + eps_t
transition eq
y_t+h = (I -exp(-hL))theta + exp(-hL)y_t+ eta_{t+h}.
The problem is that the distribution of the innovations of the transition
equation depend on the previous value of the state variable.
To be exact: y_t|y_{t-1} ~N(mu, Q_t) where Q is a diagonal
2017 Jun 11
1
Memory leak in nleqslv()
Hello all,
I am relatively new to R, but enjoying it very much. I am hoping that
someone on this list can help me with an issue I am having.
I am having issues with iterations over nleqslv, in that the solver
does not appear to clean up memory used in previous iterations. I
believe I've isolated the/my issue in a small sample of code:
library(nleqslv)
cons_ext_test <- function(x){
2012 Sep 09
1
Solving a system of two equations
Hi,
I am trying to find a simple way to numerically solve a system of two
equations equal to zero with two unknowns (x_loc and y_loc). Here is a mock
data set and below it, the equations I need to solve.
theta<-c(180,135,90)/(2*pi)
x<-c(0,0,15)
y<-c(20,0,0)
0 =
-sum((y_loc-y)*(sin(theta)*(x_loc-x)-cos(theta)*(y_loc-y))/(((x_loc-x)^2+(y_loc-y)^2)^0.5)^3)
0 =
2011 Aug 14
1
Solving a equation
Hi there, I have following equations to be solved for a and b:
a/(a+b) = x1
ab/((a+b)^2 (a+b+1)) = x2
Is there any direct function available to solve them without
disentangling them manually? Thanks for your help.
2012 Jul 23
2
Solving equations in R
Hi there,
I would like to solve the following equation in R to estimate 'a'. I have
the amp, d, x and y.
amp*y^2 = 2*a*(1-a)*(-a*d+(1-a)*x)^2
test data:
amp = 0.2370 y=
0.0233 d=
0.002 x=
0.091
Can anyone suggest how I can set this up?
Thanks,
Diviya
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2017 Feb 09
3
Ancient C /Fortran code linpack error
> > On 9 Feb 2017, at 16:00, G?ran Brostr?m <goran.brostrom at umu.se> wrote:
> >
> > In my package 'glmmML' I'm using old C code and linpack in the optimizing procedure. Specifically, one part of the code looks like this:
> >
> > F77_CALL(dpoco)(*hessian, &bdim, &bdim, &rcond, work, info);
> > if (*info == 0){
> >
2010 Mar 11
4
help about solving two equations
I have two matrix s1 and s2, each of them is 1000*1.
and I have two equations:
digamma(p)-digamma(p+q)=s1,
digamma(q)-digamma(p+q)=s2,
and I want to sovle these two equations to get the value of x and y, which are also two 1000*1 matrices.
I write a program like this:
f <- function(x) {
p<- x[1]; q <- x[2];
((digamma(p)-digamma(p+q)-s1[2,]) )^2 +((digamma(q)-digamma(p+q)-s2[2,]) )^2
2011 Dec 19
1
None-linear equality constrained optimisation problems
Dear R users,
I have a problem. I would like to solve the following:
I have
pL = 1/(1+e^(-b0+b1))
pM = 1/(1+e^(-b0))
pH = 1/(1+e^(-b0-b1))
My target function is
TF= mean(pL,pM,pH) which must equal 0.5%
My non-linear constraint is
nl.Const = 1-(pM/pH), which must equal 20%, and would like the values of
both b0 and b1 where these conditions are met.
I have searched widely for an answer,
2017 Feb 09
3
Ancient C /Fortran code linpack error
In my package 'glmmML' I'm using old C code and linpack in the
optimizing procedure. Specifically, one part of the code looks like this:
F77_CALL(dpoco)(*hessian, &bdim, &bdim, &rcond, work, info);
if (*info == 0){
F77_CALL(dpodi)(*hessian, &bdim, &bdim, det, &job);
........
This usually works OK, but with an ill-conditioned data
2010 Sep 02
3
Simultaneous equations
Dear all,
I am relatively new to R and have had some difficulty in understanding the
user manual for a package that I have downloaded to evaluate non-linear
simultaneous equations.
The package is called systemfit.
Does anyone have any experience of this package?
What I am trying to do is solve a non linear simultaneous equations...
Could anyone give me an example (please) of the code that
2012 Dec 04
1
Solve system of equations (nleqslv) only returns origin
I'm solving 4 complex equations simultaneously. Code is below. The code
returns only zero's for the solution though there should also be a non-zero
result. I'm pretty confident that the equations are correct because they
are straight from a published paper and I checked them pretty thoroughly.
The parameter values I used are from the published paper as well. Any
suggestions for how