Displaying 20 results from an estimated 6502 matches for "simulation".
2011 Mar 20
2
Why unique(sample) decreases the performance ?
...x2,x3,x4),ncol=5)
Y <- matrix(y,ncol=1)
Design.data <- cbind(X, Y)
for (j in 1:nrow(X)) {
result <- vector("list", )
for( i in 1: 3100) {
data <- Design.data[sample(50,50,replace=TRUE),] ##### and
unique(Design.data.....)
dataX <- data[,1:5]
dataY <- data[,6]
B.cap.simulation <- solve(crossprod(dataX)) %*% crossprod(dataX, dataY)
P.simulation <- dataX %*% solve(crossprod(dataX)) %*% t(dataX)
Y.cap.simulation <- P.simulation %*% dataY
e.simulation <- dataY - Y.cap.simulation
dX.simulation <- nrow(dataX) - ncol(dataX)
var.cap.simulation <- crossprod(e.si...
2007 May 08
3
plotting a point graph with data in X-axis
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2019 Dec 27
2
"simulate" does not include variability in parameter estimation
Hello, All:
????? The default "simulate" method for lm and glm seems to ignore the
sampling variance of the parameter estimates;? see the trivial lm and
glm examples below.? Both these examples estimate a mean with formula =
x~1.? In both cases, the variance of the estimated mean is 1.
??? ??????? * In the lm example with x0 = c(-1, 1), var(x0) = 2, and
2009 Feb 12
3
proposed simulate.glm method
...ctually a little dangerous
for a naive user who might be tempted to try
simulate(X) where X is a glm fit instead, because
it defaults to simulate.lm (since glm inherits from
the lm class), and the answers make no sense ...
Here is my simulate.glm(), which is modeled on
simulate.lm . It implements simulation for poisson
and binomial (binary or non-binary) models, should
be easy to implement others if that seems necessary.
I hereby request comments and suggest that it wouldn't
hurt to incorporate it into base R ... (I will write
docs for it if necessary, perhaps by modifying ?simulate --
there i...
2019 Dec 27
1
"simulate" does not include variability in parameter estimation
On 2019-12-27 04:34, Duncan Murdoch wrote:
> On 26/12/2019 11:14 p.m., Spencer Graves wrote:
>> Hello, All:
>>
>>
>> ? ????? The default "simulate" method for lm and glm seems to ignore the
>> sampling variance of the parameter estimates;? see the trivial lm and
>> glm examples below.? Both these examples estimate a mean with formula =
>>
2010 Mar 01
0
Simulation conference -- possible R opportunity
I have been talking with Gabriel Wainer about the possibility of some community building
with R and simulation workers. The conference announced below is just before UseR (but in
that capital to the north of Washington).
If anyone on this list is participating or thinking of participating, perhaps they could
let me know off-list. Ottawa-Gatineau R User Group would likely try to set up some
informal meet...
2009 Jan 08
2
VaR-Monte carlo Simulation, Historic simulation, Variance-Covariance Simulation
Dear R helpers
Suppose I have a portfolio of securities with exposure to Equity, Bonds and Forex (say $ 1000000 each).
Is there any fucntion in R that will help me calculate Value at Risk (VaR) using Monte carlo Simulation , Historic simulation and Variance - Covariance Simulation.
With regards
Maithili
2012 Mar 22
4
getting multiple plots on a single plot
...ll,
I have the following R script :
#!/usr/bin/Rscript
out_file = "hybrid.pdf"
pdf(out_file, height=8.5, width=11)
myvalues_1M <- read.csv("hybrid_sims_1M.csv",head=TRUE,sep=",")
plot(myvalues_1M$num_sims_per_thread,myvalues_1M$time_per_sim,xlab="Number
of Simulations per Thread",ylab="Time per 1 million Simulations(in
milliseconds)",col="red",main="For 1 million simulations")
lines(myvalues_1M$num_sims_per_thread,myvalues_1M$time_per_sim,col="red")
myvalues_5M <- read.csv("hybrid_sims_5M.csv",head=TRUE...
2008 Nov 16
3
chisq.test with simulate.p.value=TRUE (PR#13292)
Full_Name: Reginaldo Constantino
Version: 2.8.0
OS: Ubuntu Hardy (32 bit, kernel 2.6.24)
Submission from: (NULL) (189.61.88.2)
For many tables, chisq.test with simulate.p.value=TRUE gives a p value that is
obviously incorrect and inversely proportional to the number of replicates:
> data(HairEyeColor)
> x <- margin.table(HairEyeColor, c(1, 2))
>
2019 Dec 27
0
"simulate" does not include variability in parameter estimation
On 26/12/2019 11:14 p.m., Spencer Graves wrote:
> Hello, All:
>
>
> ????? The default "simulate" method for lm and glm seems to ignore the
> sampling variance of the parameter estimates;? see the trivial lm and
> glm examples below.? Both these examples estimate a mean with formula =
> x~1.? In both cases, the variance of the estimated mean is 1.
That's how
2012 Oct 26
3
how to make simulation faster
Dear R users,
I need to run 1000 simulations to find maximum likelihood estimates. I
print my output as a vector. However, it is taking too long. I am running 50
simulations at a time and it is taking me 30 minutes. Once I tried to run
200 simulations at once, after 2 hours I stopped it and saw that only about
40 of them are simulated in th...
2006 May 08
3
GARCH SIMULATION
Hi All,
I,m trying to do a GARCH simulation in R 2.3.0 release
in Windows XP. I've seen garchsim function but that is
for garch (1,1) and ?garch gives an example for ARCH
simulation. Can anyone help me how can i extend the
help shown in ?garch to GARCH simulation? Please help
me in this regard.
Thanks,
Sumanta Basak.
2000 Aug 10
2
help with matrix creation
hi R-help!
I would like to know a simple and easy way (if posible) to do the following
data manipulation. I have a matrix of experimental data (with replicae in time)
>experiment<-data.frame(times=c(0,0,10,10,20,20,30,30),expval=c(1,1,2,2,3,3,4,4))
> experiment
times expval
1 0 1
2 0 1
3 10 2
4 10 2
5 20 3
6 20 3
7 30 4
8
2004 Jul 24
3
Population simulation.
Hello,
can anyone tell me if R has any special function for simulating the structure
of human populations? Something like the genetic algorithm?
I need to simulate a sample of a population with a specific structure. Is
there something on R that can help me?
Thanks to everyone.
__________________________________________________________
2009 Feb 24
2
Simulating contingency table (Basic question, help please)
I'd like to carry out a Monte Carlo simulation test where given data is a
contingency table. I think this is something to do with using rmultinonom(),
but I'm not sure how to code this, to simulate contingency tables. Could
anyone please help with how to use R to simulate contingency tables like
this?
--
View this message in context: http:...
2007 Aug 02
1
simulate() and glm fits
Dear All,
I have been trying to simulate data from a fitted glm using the simulate()
function (version details at the bottom). This works for lm() fits and
even for lmer() fits (in lme4). However, for glm() fits its output does
not make sense to me -- am I missing something or is this a bug?
Consider the following count data, modelled as gaussian, poisson and
binomial responses:
counts
2011 Sep 23
4
'save' saved object names instead of objects
Hello,
I created an array to hold the results of a series of simulations I'm
running:
d.eta <- array(0,dim=c(3,3,200))
<simulation goes here and populates the array but it's not important>
Then I tried to save the results using this:
save(d.eta,file="D:/Simulation Results/sim 9-23-11 deta")
When I later tried to reload them using this:...
2008 Jul 22
1
help with simulate AR(1) data
Hi, sorry for bothering your guys again.
I want to simulate 100 AR(1) data with cor(x_t, x_t-1)=rho=0.3. The mean of
the first 70 data (x_1 to x_70) is 0 and the mean of the last 30 data (x_71
to x_100) is 2. Can I do it in the following way?
x <- arima.sim(list=(ar=0.3), 100)
mean <- c(rep(0, 70), rep(2, 30))
xnew <- x+mean
If the above code to simulate 100 AR(1) data is right, what
2008 May 24
5
Simulating the p-value of a test statistic
Dear Friends,
I want to know if any one could give me help on this.
Suppose you want to simulate the p-value of a test statistic
but you do not know how the distribution of the test
statistic, how can one simulate the p-value.
It will be helpful to get an example code in R on this
Respectfully Submitted,
Clement
2007 Jun 02
2
spatial simulation
Dear R-users,
I'm trying to do some spatial simulation. I have two covariates, Z and C. I want to examine their relationship under different spatial distribution.
I have no problem simulating completely spatial random process but I'm totally stuck on poisson (cluster) pattern. I already have a dataset with Z and C (obs=575) and I know the relatio...