Displaying 12 results from an estimated 12 matches for "lam1".
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lam
2006 Oct 03
1
do.call with Vectorial Argument
...function are given
with a vector (I need to express then this way to be able later on to
integrate them numerically with the adapt package).
Consider the small script:
remove(list=ls())
#library(adapt)
# first a list of the parameters
tau<-0.1
beta<-1/tau
St<-tau
D=2e-2
q<-2*beta^2*D
lam1<- -beta/2*(1+sqrt(1-4*St))
lam2<- -beta/2*(1-sqrt(1-4*St))
x0<- 0
vx0<- 1
# fist a function with scalar parameters
sigma_pos_old<-function(t,q,lam1,lam2)
{
q/(lam1-lam2)^2*(
(exp(2*lam1*t)-1)/(2*lam1)-2/(lam1+lam2)*(exp(lam1*t+lam2*t)-1) +
(exp(2*lam2*t)-1)/(2*lam2) )
}
# now the...
2006 Sep 22
4
Creating Movies with R
...e user.
I wonder if it is possible to use the data generated for different
times to create something like an .avi file.
Here is the script:
rm(list=ls())
library(lattice)
# I start defining the analytical functions needed to get the density
as a function of time
expect_position <- function(t,lam1,lam2,pos_ini,vel_ini)
{1/(lam1-lam2)*(lam1*exp(lam2*t)-lam2*exp(lam1*t))*pos_ini+
1/(lam1-lam2)*(exp(lam1*t)-exp(lam2*t))*vel_ini
}
sigma_pos<-function(t,q,lam1,lam2)
{
q/(lam1-lam2)^2*(
(exp(2*lam1*t)-1)/(2*lam1)-2/(lam1+lam2)*(exp(lam1*t+lam2*t)-1) +
(exp(2*lam2*t)-1)/(2*lam2) )
}
rho_x<-...
2010 Nov 15
2
Zero truncated Poisson distribution & R2WinBUGS
...counted during the 3 consecutive visits
(2) The second part of the script calls WinBUGS and run the binomial
mixture models on the count data. In this case the count matrix y was
converted to a vector C1 before being passed over to BUGS
Any idea how to create a zero truncated Poisson for parameter lam1
(i.e., parameter lambda of the Poisson distribution)
Thank you for your help.
#R script
#Simulated abundance data
n.site <- 200# 200 sites visited
lam <- 5 #mean number of animals per site
R <- n.site # nubmer of sites
T <- 3 # Number of replicate counts at each site
N=rpois(n = n....
2009 Nov 09
0
unexpected results involving the skellam distribution
...kellam-distributed random variable
with respect to the skellam distribution.
I would expect to get random errors, but the plot
sistematically shows a non-random pattern (first a
peak and then a low). I don't know how to explain
this. Can somebody enlighten me??
require(skellam)
n <- 5000
lam1 <- 5.45
lam2 <- 2.78
p1 <- rpois(n, lam1)
p2 <- rpois(n, lam2)
rho <- cor(p1,p2)
z <- hist(p1-p2, plot=FALSE)
mu1 <- lam1 - (rho*sqrt(lam1*lam2))
mu2 <- lam2 - (rho*sqrt(lam1*lam2))
x <- z$breaks[1:length(z$breaks)-1]
y <- dskellam(x, mu1, mu2)
plot(x,z$density-y)...
2013 Mar 18
1
"save scores" from sem
...by multiplication the manifest
variable vector with the estimates for the specific effect.
To make an example:
v1; v2; v3; v4 are manifest variables that loads on one y latent
variablein a data frame called "A"
the code for the model should be like:
model <-specifymodel(
y -> v1, lam1, NA
y -> v2, lam2, NA
y -> v3, lam3, NA
y -> v4, lam4, NA
After fitting the model with sem
model.sem <- sem(model, data=A)
you should be able to compute the y variable like:
attach(data)
data$y<-v1*lam1+v2*lam2+v3*lam3+v4*lam4 #change the loading name with
the actual loading (num...
2006 Aug 22
1
Total (un)standardized effects in SEM?
Hi there,
as a student sociology, I'm starting to learn about SEM. The course I
follow is based on LISREL, but I want to use the SEM-package on R
parallel to it.
Using LISREL, I found it to be very usable to be able to see the
total direct and total indirect effects (standardized and
unstandardized) in the output. Can I create these effects using R? I
know how to calculate them
2012 Mar 23
0
Fixing error variance in a path analysis to model measurement error in scales using sem package
...(rRU))
power_alt -> em, iota1
power_alt <-> power_alt, NA, (1 - alpha(power_alt))*(variance(power_alt))
ms_alt -> em, zeta1
ms_alt <-> ms_alt, NA, (1 - alpha(ms_alt))*(variance(ms_alt))
em -> relM1, eta1
em <-> em, NA, (1 - alpha(em))*(variance(em))
relM1 <-> relM1, lam1
After testing this model, the model fits were unnaceptable and package sem
could not compute modification instances. In contrast, when I do not fix
error variances, after a few modifications to the model, I am able to reach
a theoretical cogent model that has acceptable model fits.
I have several...
2013 Mar 12
1
Bootstrap BCa confidence limits with your own resamples
I like to bootstrap regression models, saving the entire set of bootstrapped
regression coefficients for later use so that I can get confidence limits
for a whole set of contrasts derived from the coefficients. I'm finding
that ordinary bootstrap percentile confidence limits can provide poor
coverage for odds ratios for binary logistic models with small N. So I'm
exploring BCa confidence
2011 May 16
0
SEM Model Not Converging
....default(ram = ram, S = S, N = N, param.names = pars, var.names = vars, :
Could not compute QR decomposition of Hessian.
Optimization probably did not converge.
I tried setting par.size='startvalues' and it didn't make any
difference. Is it just the size of my model?
F1->reFDE, lam1, NA
F1->ReFUIDGreg, lam2, NA
F1->reFDRwithDDRV, lam3, NA
F1->reparD, lam4, NA
F1->reparDR, lam5, NA
F1->reparRisk, lam6, NA
F1->reWDD, lam7, NA
F1->reWDH, lam8, NA
F1->reWSP, lam9, NA
F1->reWDIS, lam10, NA
F1->reWCell, lam11, NA
F1->reWFAT, lam12, NA
F1->reAanx,...
2009 Mar 30
2
HELP WITH SEM LIBRARY AND WITH THE MODEL'S SPECIFICATION
...,X$X3h,X$X3i,X$X3l,X$X3m,X$X3n,X$X3o,X$X3p,X$X3q,X$X3r,X$X3s,X$X3t,X$X3u,X$X3v,X$X4a,X$X5q,X$X5r,X$X5s,X$X8a,X$X8b,X$X8c,X$X8d)
#i calculate the covariance of the data
mydata.cov <- cov(mydata,use="complete.obs")
#I specify my model
model.mydata <- specify.model()
F1 -> X.X12a, lam1, NA
F1 -> X.X12b, lam2, NA
F1 -> X.X12c, lam3, NA
F1 -> X.X12d, lam4, NA
F1 -> X.X12e, lam5, NA
F1 -> X.X12f, lam6, NA
F1 -> X.X12g, lam7, NA
F2 -> X.X12h, lam8, NA
F2 -> X.X12i, lam9, NA
F2 -> X.X12l, lam10, NA
F2 -> X.X12m, lam11, NA
F2 -> X.X12n,...
2008 Apr 01
4
Trying to get Effect.Appear, Scale, Fade to work
=================================================
Mon-03-31-2008, 11:04pm U.S.EDT
Hello,
I''m trying to get a website entry page to work properly, while
learning Scriptaculous effects and javascript at the same time. I
wanted to use a couple of effects to add a little flash-style
animation. I managed to get the initial Appear to work but with a
problem: the image that''s supposed
2009 Apr 01
0
回复: R-help Digest, Vol 73, Issue 32
...,X$X3h,X$X3i,X$X3l,X$X3m,X$X3n,X$X3o,X$X3p,X$X3q,X$X3r,X$X3s,X$X3t,X$X3u,X$X3v,X$X4a,X$X5q,X$X5r,X$X5s,X$X8a,X$X8b,X$X8c,X$X8d)
#i calculate the covariance of the data
mydata.cov <- cov(mydata,use="complete.obs")
#I specify my model
model.mydata <- specify.model()
F1 -> X.X12a, lam1, NA
F1 -> X.X12b, lam2, NA
F1 -> X.X12c, lam3, NA
F1 -> X.X12d, lam4, NA
F1 -> X.X12e, lam5, NA
F1 -> X.X12f, lam6, NA
F1 -> X.X12g, lam7, NA
F2 -> X.X12h, lam8, NA
F2 -> X.X12i, lam9, NA
F2 -> X.X12l, lam10, NA
F2 -> X.X12m, lam11, NA
F2 -> X.X12n,...