Displaying 20 results from an estimated 700 matches similar to: "spatstat regression troubles"
2007 Mar 21
2
Gaussian Adaptive Quadrature
Hi all,
Does anybody know any function that performs gaussian adapative quadrature integration of univariate functions?
Thanks in advance,
Regards,
Caio
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2008 Mar 12
3
Types of quadrature
Dear R-users
I would like to integrate something like \int_k^\infty (1 - F(x)) dx, where F(.) is a cumulative distribution function. As mentioned in the "integrate" help-page: integrate(dnorm,0,20000) ## fails on many systems. This does not happen for an adaptive Simpson or Lobatto quadrature (cf. Matlab). Even though I am hardly familiar with numerical integration the implementation
2009 May 08
1
ADAPTIVE QUADRATURE WEIGHTS AND NODES
Can anyone help me on how to get the nodes and weights of the adaptive quadrature
using R.
Best wishes
Boikanyo.
-----
The University of Glasgow, charity number SC004401
2013 Oct 11
3
Gaussian Quadrature for arbitrary PDF
Hi all,
We know that Hermite polynomial is for
Gaussian, Laguerre polynomial for Exponential
distribution, Legendre polynomial for uniform
distribution, Jacobi polynomial for Beta distribution. Does anyone know
which kind of polynomial deals with the log-normal, Studentæ¯ t, Inverse
gamma and Fisheræ¯ F distribution?
Thank you in advance!
David
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2011 Apr 28
0
fit a marked poisson process using a quadrature scheme with 'spatstat'
Hello everyone,
My data consists of marked points and several covariates, whereby the marks
are the time points of the observations. The problem is, that one of the
covariates is hard to handle as an image. This covariate represents the type
of roads. As there aren't roads at every location of the map, one cannot
specify the value of the covariate at any point on a grid, which is
necessary to
2006 Apr 28
1
gauss.quad.prob
I've written a series of functions that evaluates an integral from -inf to a or b to +inf using equally spaced quadrature points along a normal distribution from -10 to +10 moving in increments of .01. These functions are working and give very good approximations, but I think they are computationally wasteful as I am evaluating the function at *many* points.
Instead, I would prefer to use
2008 Sep 27
3
Double integration - Gauss Quadrature
Hi,
I would like to solve a double integral of the form
\int_0^1 \int_0^1 x*y dx dy
using Gauss Quadrature.
I know that I can use R's integrate function to calculate it:
integrate(function(y) {
sapply(y, function(y) {
integrate(function(x) x*y, 0, 1)$value
})
}, 0, 1)
but I would like to use Gauss Quadrature to do it.
I have written the following code (using R's statmod package)
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
2011 Nov 06
2
how to use quadrature to integrate some complicated functions
Hello to all,
I am having trouble with intregrating a complicated uni-dimensional function
of the following form
Phi(x-a_1)*Phi(x-a_2)*...*Phi(x-a_{n-1})*phi(x-a_n).
Here n is about 5000, Phi is the cumulative distribution function of
standard normal,
phi is the density function of standard normal, and x ranges over
(-infty,infty).
My idea is to to use quadrature to handle this integral. But
2006 Aug 22
1
a generic Adaptive Gauss Quadrature function in R?
Hi there,
I am using SAS Proc NLMIXED to maximize a likelihood with
multivariate normal random effects. An example is the two part random
effects model for repeated measures semi-continous data with a
cluster at 0. I use the "model y ~ general(loglike)" statement in
Proc NLMIXED, so I can specify a general log likelihood function
constructed by SAS programming statements. Then the
2008 Aug 21
2
Help Regarding 'integrate'
I have an R function defined as:
f<-function(x){
return(dchisq(x,9,77)*((13.5/x)^5)*exp(-13.5/x))
}
Numerically integrating this function, I observed a couple of things:
A) Integrating the function f over the entire positive real line gives an
error:
> integrate(f,0,Inf)
Error in integrate(f, 0, Inf) : the integral is probably divergent
B) Increasing the interval of integration
2010 Sep 29
1
nlminb and optim
I am using both nlminb and optim to get MLEs from a likelihood function I have developed. AFAIK, the model I has not been previously used in this way and so I am struggling a bit to unit test my code since I don't have another data set to compare this kind of estimation to.
The likelihood I have is (in tex below)
\begin{equation}
\label{eqn:marginal}
L(\beta) = \prod_{s=1}^N \int
2010 Oct 08
1
Trapezoid Rule
Dear R Users,
I've never used R before and my professor has asked us to do some
pretty intense programming (or it's intense to me at least). Here is
the question: Modify the function myquadrature inside the script so
that it returns the quadrature of descrete data using the trapezoidal
rule. Modify the call to the function at the bottom of the script so
that is uses your modifies
2012 Aug 02
3
Need Help in Finite Element Analysis
Hi everybody
I need help to solve the following problem in finite element
A field variable f(x,y)=x? y is defined over a rectangle domain
?={K: 0?x?4 , 0?y?6? Given the expression
g=?_(0 0)^(6 4)??X^3 Y dx dy?
And assume the following bilinear interpolation shape functions are used to
discretize the spatial geometric variable x and y:
N1= ? (1-z)(1-e)
N1= ? (1+z)(1-e)
N1= ? (1+z)(1+e)
N1=
2011 Sep 23
1
Cross Spectrum : Conversion of 2-D spectrum into a single complex array
Hi, I'm wondering why the spectrum() phase of quadrature
couple isn't purely +/-pi.
But mostly, I'm looking for a recommended way to take a 2-D
spectrum and convert it into a single complex array.
Kindly consider:
# 10 Hz sine wave 10 seconds long sampled at 50 Hz
deltaT = 1/50
t = seq(0, 10, deltaT)
w = 2 * pi * 10
x = ts( sin( w * t ), deltat = deltaT )
y = ts( sin(
2002 Apr 20
2
integration of a discrete function
Dear R list
I am looking for a function in R that computes the integration of a
discrete curve, such as a power spectrum, in a specified interval (in my
case, that would be 'power in a certain frequency band'). I found only
functions, such as 'integrate', that perform adaptive quadrature on
analytic functions, and not on a curve specified as a set of (x,y) pairs.
I have the
2005 May 06
2
bivariate normal cdf
-- R Help List --
I am looking for a bivariate normal cdf routine in R. I have some fortran routines for this, which appear to be based on 15-point quadrature. Any guidance/suggestions on making these in loadable R-functions would be appreciated.
Thanks,
Dan
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Daniel A. Powers, Ph.D.
Department of Sociology
University of Texas at Austin
2010 Sep 21
3
bivariate vector numerical integration with infinite range
Dear list,
I'm seeking some advice regarding a particular numerical integration I
wish to perform.
The integrand f takes two real arguments x and y and returns a vector
of constant length N. The range of integration is [0, infty) for x and
[a,b] (finite) for y. Since the integrand has values in R^N I did not
find a built-in function to perform numerical quadrature, so I wrote
my own after
2018 Jan 17
1
mgcv::gam is it possible to have a 'simple' product of 1-d smooths?
I am trying to test out several mgcv::gam models in a scalar-on-function regression analysis.
The following is the 'hierarchy' of models I would like to test:
(1) Y_i = a + integral[ X_i(t)*Beta(t) dt ]
(2) Y_i = a + integral[ F{X_i(t)}*Beta(t) dt ]
(3) Y_i = a + integral[ F{X_i(t),t} dt ]
equivalents for discrete data might be:
1) Y_i = a + sum_t[ L_t * X_it * Beta_t ]
(2) Y_i
2008 Apr 26
1
integration error when I use "optim" and "integrate" simultaneously
Dear R users,
When I use two functions, 'optim' and 'integrate', simultaneously, I always
get an error like this
--------------------------------------------------------------------------
numint = function(z) {
dlnorm(z,mu[1],sqrt(exp(g[1]))) *
dnorm((z-mu[2])/sqrt(exp(g[2])))/sqrt(exp(g[2]))
}
integrate(numint,lower=0,upper=Inf)$value
Error in integrate(numint, lower = 0,