Displaying 20 results from an estimated 1000 matches similar to: "transform R to C"
2009 May 16
1
maxLik pakage
Hi all;
I recently have been used 'maxLik' function for maximizing G2StNV178 function with gradient function gradlik; for receiving this goal, I write the following program; but I have been seen an error in calling gradient function;
The maxLik function can't enter gradlik function (definition of gradient function); I guess my mistake is in line ******** ,that the vector ‘h’ is
2006 Jul 07
1
convert ms() to optim()
How to convert the following ms() in Splus to Optim in R? The "Calc" function is also attached.
ms(~ Calc(a.init, B, v, off, d, P.a, lambda.a, P.y, lambda.y,
10^(-8), FALSE, 20, TRUE)$Bic,
start = list(lambda.a = 0.5, lambda.y = 240),
control = list(maxiter = 10, tol = 0.1))
Calc <- function(A.INIT., X., V., OFF., D.,
P1., LAMBDA1., P2., LAMBDA2.,
TOL., MONITOR.,
2008 Sep 12
1
Error in "[<-"(`*tmp*`, i, value = numeric(0)) :
I use "while" loop but it produces an errro. I have no idea about this.
Error in "[<-"(`*tmp*`, i, value = numeric(0)) :
nothing to replace with
The problem description is
The likelihood includes two parameters to be estimated: lambda
(=beta0+beta1*x) and alpha. The algorithm for the estimation is as
following:
1) with alpha=0, estimate lambda (estimate beta0
2008 Sep 19
2
Error: function cannot be evaluated at initial parameters
I have an error for a simple optimization problem. Is there anyone knowing
about this error?
lambda1=-9
lambda2=-6
L<-function(a){
s2i2f<-(exp(-lambda1*(250^a)-lambda2*(275^a-250^a))
-exp(-lambda1*(250^a)-lambda2*(300^a-250^a)))
logl<-log(s2i2f)
return(-logl)}
optim(1,L)
Error in optim(1, L) : function cannot be evaluated at initial parameters
Thank you in advance
--
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2001 Sep 14
1
Supply linear constrain to optimizer
Dear R and S users,
I've been working on fitting finite mixture of negative exponential
distributions using maximum likelihood based on the example given in MASS.
So far I had much success in fitting two components. The problem started
when I tried to extend the procedure to fit three components.
More specifically,
likelihood = sum( ln(c1*exp(-x/lambda1)/lambda1 +
c2*exp(-x/lambda2)/lambda2
2006 Jul 14
1
Optim()
Dear all,
I have two functions (f1, f2) and 4 unknown parameters (p1, p2, p3, p4). Both
f1 and f2 are functions of p1, p2, and p3, denoted by f1(p1, p2, p3) and
f2(p1,p2,p3) respectively.
The goal is to maximize f1(p1, p2, p3) subject to two constraints:
(1) c = k1*p4/(k1*p4+(1-k1)*f1(p1,p2,p3)), where c and k1 are some known
constants
(2) p4 = f2(p1, p2, p3)
In addition, each parameter
2009 Aug 25
1
Elastic net in R (enet package)
Dear R users,
I am using "enet" package in R for applying "elastic
net" method. In elastic net, two penalities are applied one is lambda1 for
LASSO and lambda2 for ridge ( zou, 2005) penalty. But while running the
analysis, I realised tht, I optimised only one lambda. ( even when I
looked at the example in R, they used only one penality) So, I am
2008 Sep 11
0
Loop for the convergence of shape parameter
Hello,
The likelihood includes two parameters to be estimated: lambda
(=beta0+beta1*x) and alpha. The algorithm for the estimation is as
following:
1) with alpha=0, estimate lambda (estimate beta0 and beta1 via GLM)
2) with lambda, estimate alpha via ML estimation
3) with updataed alpha, replicate 1) and 2) until alpha is converged to a
value
I coded 1) and 2) (it works), but faced some
2009 Oct 14
1
different L2 regularization behavior between lrm, glmnet, and penalized?
The following R code using different packages gives the same results for a
simple logistic regression without regularization, but different results
with regularization. This may just be a matter of different scaling of the
regularization parameters, but if anyone familiar with these packages has
insight into why the results differ, I'd appreciate hearing about it. I'm
new to
2011 Jun 14
2
How to generate bivariate exponential distribution?
Any one know is there any package or function to generate bivariate
exponential distribution? I gusee there should be three parameters, two rate
parameters and one correlation parameter. I just did not find any function
available on R. Any suggestion is appreciated.
--
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2008 Nov 15
1
rgamma with rate as vector
Hi - I have a question about the following code from Bayesian
Computation with R (Jim Albert).
par(mfrow=c(2,2))
m = 500
alphas = c(5, 20, 80, 400)
for (j in 1:4) {
mu = rgamma(m, shape=10, rate=10)
lambda1 = rgamma(m, shape=alphas[j], rate=alphas[j]/mu)
lambda2 = rgamma(m, shape=alphas[j], rate=alphas[j]/mu)
plot(lambda1, lambda2)
title(main=paste('alpha=',
2010 Nov 15
2
Zero truncated Poisson distribution & R2WinBUGS
I am using a binomial mixture model to estimate abundance (N) and
detection probability (p) using simulated count data:
-Each site has a simulated abundance that follow a Poisson
distribution with lambda = 5
-There are 200 simulated sampled sites
-3 repeated counts at each site
- only 50 percent of the animals are counted during each count (i.e,
detection probability p =0.5, see codes)
We removed
2023 Aug 27
1
Query on finding root
On Fri, 25 Aug 2023 22:17:05 +0530
ASHLIN VARKEY <ashlinvarkey at gmail.com> wrote:
> Sir,
Please note that r-help is a mailing list, not a knight! ??
> I want to solve the equation Q(u)=mean, where Q(u) represents the
> quantile function. Here my Q(u)=(c*u^lamda1)/((1-u)^lamda2), which is
> the quantile function of Davies (Power-pareto) distribution. Hence I
> want to
2017 Oct 31
0
lasso and ridge regression
Dear All
The problem is about regularization methods in multiple regression when the
independent variables are collinear. A modified regularization method with
two tuning parameters l1 and l2 and their product l1*l2 (Lambda 1 and
Lambda 2) such that l1 takes care of ridge property and l2 takes care of
LASSO property is proposed
The proposed method is given
2010 Oct 25
0
penalized regression analysis
Hi All,
I am using the package 'penalized' to perform a multiple regression on a
dataset of 33 samples and 9 explanatory variables. The analysis appears to
have performed as outlined and I have ended up with 4 explanatory variables
and their respective regression coefficients. What I am struggling to
understand is where do I get the variance explained information from and how
do I
2007 Aug 14
2
State Space Modelling
Hey all,
I am trying to work under a State Space form, but I didn't get the help
exactly.
Have anyone eles used this functions?
I was used to work with S-PLUS, but I have some codes I need to adpt.
Thanks alot,
Bernardo
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2008 Aug 21
1
pnmath compilation failure; dylib issue?
(1) ...need to speed up a monte-carlo sampling...any suggestions about
how I can get R to use all 8 cores of a mac pro would be most useful
and very appreciated...
(2) spent the last few hours trying to get pnmath to compile under os-
x 10.5.4...
using gcc version 4.2.1 (Apple Inc. build 5553) as downloaded from
CRAN, xcode 3.0...
...xcode 3.1 installed over top of above after
2017 Dec 08
0
Elastic net
Dear R users,?
? ? ? ? ? ? ? ? ? ? ? ? I am using "Glmnet" package in R for applying "elastic net" method. In elastic net, two penalities are applied one is lambda1 for?LASSO and lambda2 for ridge ( zou, 2005) penalty.?How can I? write the code to? pre-chose the? lambda1 for?LASSO and lambda2 for ridge without using cross-validation
Thanks in advance?
Tayo?
[[alternative
2001 Sep 17
0
Many thanks. (Was: Supply linear constrain to optimizer)
Many thanks to those took time replied to my question. They were very
helpful and I solved my problem by reparameterization. With the help of
optim() the fitting procedure is very robust and insensitive to initial
starting value.
Once again, many thanks.
Kevin
-------- Original post ---------
>Dear R and S users,
>
>I've been working on fitting finite mixture of negative
2007 Mar 11
1
fitting a mixed exponential distribution
Hi all,
I am attempting to fit, and test the goodness of fit of, a mixed
exponential distribution to my dataset which consists of 15minute
rainfall intensity data. FYI, the dataset spanning approx.2 years and
7 rainfall stations consists of some three hundred thousand 15min data
records, of which some 30 thousand are non-zero rainfall amounts.
Could anyone please tell me how i could do