Displaying 20 results from an estimated 20000 matches similar to: "Double integration using R"
2010 Aug 03
1
[LLVMdev] Replacing types, use of refineAbstractType
I'm working on a personal project which involves lowering a superset of
LLVM to "vanilla" LLVM. Part of this involves rewriting types. I'm
working off of the 2.6 code base, so this may have been addressed in a bug
fix.
I'm having trouble with refineAbstractType and recursive types.
Specifically, I'm creating opaque types to serve as placeholders for the
final
2014 Sep 30
2
[LLVMdev] Behaviour of NVPTX intrinsic
I have written test.ll as below and ran 'opt' on it as
" opt -std-compile-opts test.ll -S -o -" . But the output shows that there
is code motion around the barrier intrinsics.
test.ll
-------
; ModuleID = 'test.bc'
define void @test(i16* %I_0, i16* %I_1, i16* %I_2, i16* %I_3, i16* %O_0) {
entry:
%T_0 = load volatile i16* %I_0
%T_1 = load volatile i16* %I_1
%T_2 =
2012 Mar 23
3
R numerical integration
Hi all,
Is there any other packages to do numerical integration other than the
default 'integrate'?
Basically, I am integrating:
integrate(function(x) dnorm(x,mu,sigma)/(1+exp(-x)),-Inf,Inf)$value
The integration is ok provided sigma is >0.
However, when mu=-1.645074 and sigma=17535.26
It stopped working. On the other hand, Maple gives me a value of
0.5005299403.
It is an
2012 Jan 11
2
Finding percentile of a value from an empirical distribution
Hello,
I am not sure how to do this in R. Any suggestion would be
appreciated. I have a vector of values from where I build an empirical
CDF. For example:
> x <- seq(1,100)
> x <- sample(x,1000,replace=T)
> quantile(x,probs=seq(0,1,.05))
0% 5% 10% 15% 20% 25% 30% 35% 40% 45%
50% 55%
1.00 5.00 10.00 16.00 20.00 25.00 31.00 36.00 41.00
2010 Apr 14
2
Gaussian Quadrature Numerical Integration In R
Hi All,
I am trying to use A Gaussian quadrature over the interval (-infty,infty) with weighting function W(x)=exp(-(x-mu)^2/sigma) to estimate an integral.
Is there a way to do it in R? Is there a function already implemented which uses such weighting function.
I have been searching in the statmode package and I found the function "gauss.quad(100, kind="hermite")" which uses
2006 Nov 09
1
optimize function with integral form ?
Hi all,
Does anybody have the experience of using optim to estimate variables with integral forms?
here the code:
trun.mean<- function(x) # t is the threshold
{
mu=x[1];
sigma=x[2];
t=x[3];
f <- function(x) (1/(sigma*sqrt(2*pi)))*exp(-(x-mu)^2/(2*sigma^2));
pdf.fun <- function(x) x*f(x);
integrate(f,thre,upper=Inf)$value/integrate(pdf.fun,thre,upper=Inf)$value ;
}
when I
2012 Jul 20
1
fitting Ornstein-Uhlenbeck process by MAXIMUM LIKELYHOOD
Dear friends
i am trying to fit an Ornstein-Uhlenbeck process by MAXIMUM LIKELYHOOD
method.
i found these formulas on
http://www.sitmo.com/article/calibrating-the-ornstein-uhlenbeck-model/
this is the mean-reverting process
http://r.789695.n4.nabble.com/file/n4637271/process.txt process.txt
and this is the script that i am using.......
ouFit.ML=function(spread) {
n=length(spread)
2007 Jan 19
3
integrate and quadratic forms
Hi all.
I'm trying to numerically invert the characteristic function
of a quadratic form following Imhof's (1961, Biometrika 48)
procedure.
The parameters are:
lambda=c(.6,.3,.1)
h=c(2,2,2)
sigma=c(0,0,0)
q=3
I've implemented Imhof's procedure two ways that, for me,
should give the same answer:
#more legible
integral1 = function(u) {
2009 Jul 31
1
Matrix Integral
Hi,
Any help on this would be appreciated:
I need to integrate where K is a 4x4 matrix, and SIGMA is a 4x4 matrix from
say a to b, i.e. 0 to 5:
integral MatrixExp(-K * s) %*% SIGMA %*% t(SIGMA) %*% MatrixExp(t(-K) s) ds
t is tranpose , %*% : matrix mult , MatrixExp : matrix exponential
I've use integrate before on univariate functions like f(x) = x^2 which is
fine but when doing this on
2004 Nov 14
1
solving system of nonlinear equations
Hello there
Can anybody please tell me if there is any package in R to solve the
following 4 nonlinear equations with 4 unknowns:
alpha*exp(20/sigma)+ beta*exp(21/tau) = 2
alpha*exp(22/sigma)+ beta*exp(9/tau) = 4
alpha*exp(10/sigma)+ beta*exp(30/tau) = 6
alpha*exp(40/sigma)+ beta*exp(39/tau) = 5
where
alpha = exp(lambda/sigma)
beta= exp(delta/tau)
I need to estimate lambda, sigma, delta, tau
2012 Mar 22
2
Quicker way to apply values to a function
Hi all,
myint=function(mu,sigma){
integrate(function(x) dnorm(x,mu,sigma)/(1+exp(-x)),-Inf,Inf)$value
}
mymu=seq(-3,3,length(1000))
mysigma=seq(0,1,length(500))[-1]
k=1
v=c()
for (j in 1:length(mymu)) {
for (i in 1:length(mysigma)) {
v[k]=myint(mymu[j],mysigma[i])
k=k+1
}
}
Basically, I want to investigate for what values of mu and sigma, the
integral is divergent.
Is there another way
2009 Jan 02
1
R: numerical integration problems
hello all
happy new year and hope you r having a good holiday.
i would like to calculate the expectation of a particular random variable and would like to approximate it using a number of the functions contained in R. decided to do some experimentation on a trivial example.
example
========
suppose x(i)~N(0,s2) where s2 = the variance
the prior for s2 = p(s2)~IG(a,b)
so the posterior is
2001 Nov 22
2
optim ???
Hola!
santes<-c(210,169,187,160,167,176,185,206,173,146,174,201,198,148,154)
sdespues<-c(201,165,166,157,147,145,168,180,147,136,151,168,179,129,131)
dantes<-c(130,122,124,104,112,101,121,124,115,102,98,119,106,107,100)
ddespues<-c(125,121,121,106,101,85,98,105,103,98,90,98,110,103,82)
presion<-data.frame( santes, sdespues, dantes, ddespues)
logvero <-
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)
2015 Apr 10
1
RFC: sigma() in package:stats ?
I'm proposing to add something like this to the stats package :
----------------------------------------------------------
### "The" sigma in lm/nls - "like" models:
sigma <- function(object, ...) UseMethod("sigma")
## works whenever deviance(), nobs() and coef() do fine:
sigma.default <- function (object, use.fallback=TRUE, ...)
2007 Mar 07
1
Failure to run mcsamp() in package arm
Dear r-helpers,
I can run the examples on the mcsamp help page. For example:
****************************************
> M1 <- lmer (y1 ~ x + (1|group))
> (M1.sim <- mcsamp (M1))
fit using lmer,
3 chains, each with 1000 iterations (first 500 discarded)
n.sims = 1500 iterations saved
mean sd 2.5% 25% 50% 75% 97.5% Rhat n.eff
beta.(Intercept)
2007 Jul 24
1
function optimization: reducing the computing time
Dear useRs,
I have written a function that implements a Bayesian method to
compare a patient's score on two tasks with that of a small control
group, as described in Crawford, J. and Garthwaite, P. (2007).
Comparison of a single case to a control or normative sample in
neuropsychology: Development of a bayesian approach. Cognitive
Neuropsychology, 24(4):343?372.
The function (see
2005 Jun 22
1
legend
I color some area grey with polygon() (with a red border) and then I
want to have the dashed red border in the legend as well. How do I
manage it?
And I want to mix (latex) expressions with text in my legend.
Just execute my lines below and you know want I mean. Or pass by at
http://de.wikipedia.org/wiki/Bild:GBM.png to see the picture online.
Thomas
bm <- function(n=500, from=0, to=1) {
2006 Aug 26
1
Capture of iterative integration output
Hello,
I am a novice R user and am having difficulty retrieving the values
from 21 iterations of the R function integrate.
The only way I have found is to do a write.table and then a read.table
as shown in the code below. I would rather capture the 21 values inside
the braces ( sapply might work, but I can't set it up without getting an
error in function) so I could compute the
2010 Jul 01
3
Double Integration
Dear R helpers
I am working on the Bi-variate Normal distribution probabilities. I need to double integrate the following function (actually simplified form of bivariate normal distribution)
f(x, y) = exp [ - 0.549451 * (x^2 + y^2 - 0.6 * x * y) ]
where 2.696 < x < 3.54 and -1.51 < y < 1.98
I need to solve something like
INTEGRATE (2.696 to 3.54) dx INTEGRATE [(-1.51 to 1.98)]