Displaying 20 results from an estimated 900 matches similar to: "Bivariate polynomials in R"
2009 Feb 08
0
recursive derivative a list of polynomials
Dear list,
This is quite a specific question requiring the package orthopolynom.
This package provides a nice implementation of the Legendre
polynomials, however I need the associated Legendre polynomial which
can be readily expressed in terms of the mth order derivative of the
corresponding Legendre polynomial. (For the curious, I'm trying to
calculate spherical harmonics [*]).
2011 Jan 25
0
Multivariate polynomials Howto
Good Evening,
I would like to work with multivariate polynomials (x and y variables).
I know that there is a package called multipol but I am not sure that supports my needs.
I use a function (in reality legendre.polynomials) which creates me the polynomials I want.
For example the following returns
> legendre.polynomials(2)[[2]]
x (first order polynomial)
I would like to calculate the
2008 Oct 16
3
defining a function using strings
Hi All,
I need to evaluate a series expansion using Legendre polynomials.
Using the 'orthopolinom' package I can get a list of the first n
Legendre polynomials as character strings.
> library(orthopolynom)
> l<-legendre.polynomials(4)
> l
[[1]]
1
[[2]]
x
[[3]]
-0.5 + 1.5*x^2
[[4]]
-1.5*x + 2.5*x^3
[[5]]
0.375 - 3.75*x^2 + 4.375*x^4
But I can't figure out how to
2010 Dec 08
2
Legendre polynomials
Hello everyone,
I would like to find out if there are already implemented function for legendre
polynomials. I tried google but returns nothing. How do you suggest me to search
for that?
Regards
Alex
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2011 Jan 27
0
adaptIntegral takes too much time
Hello Dear List members,
as you can see (and guess) from the code below
adaptIntegrate(f,lowerLimit=c(-1,-1),upperLimit=c(.9999,.9999))
$integral
[1] 9.997e-09
$error
[1] 1.665168e-16
$functionEvaluations
[1] 17
$returnCode
[1] 0
> adaptIntegrate(f,lowerLimit=c(-1,-1),upperLimit=c(1,1))
the last command runs for 45 mins now.
-this one takes only less than sec:
2008 Jul 01
1
Orthogonal polynomials and poly
Dear All,
I have found in the poly help this sentence:
The orthogonal polynomial is summarized by the coefficients, which can be
used to evaluate it via the three-term recursion given in Kennedy & Gentle
(1980, pp. 343–4), and used in the predict part of the code.
My question: which type of orthogonal polynomials are used by this function?
Hrmite, legendre..
TIA
Giovanni
[[alternative HTML
2008 Apr 23
0
new package multipol
Hello List
please find a new package, multipol, recently uploaded to CRAN.
This package generalizes the polynom package (which handles univariate
polynomials) to the multivariate case. A short article discussing the
package will appear in the next issue of Rnews, Insha'Allah
enjoy
--
Robin Hankin
Uncertainty Analyst and Neutral Theorist,
National Oceanography Centre, Southampton
2008 Feb 04
2
a != a*1 != a+0 != +a
hits=1.0 tests=MANY_EXCLAMATIONS
X-USF-Spam-Flag: NO
Hi
I am writing a package for multivariate polynomials ('multipols')
using S3 methods.
The package includes a Ops.multipol() function for the
arithmetic methods; I would like
to define some sort of user-specified Boolean option which, if
set, would force results to be simplified as they are produced.
Call this option
2011 Feb 12
1
R limits documented?
Is there documentation on R limits?
That is, max matrix size, etc.?
Diagnostics when limits are exceeded are not always
meaningful. For example:
> x <- rep(0,50000*50000)
Error in rep(0, 50000 * 50000) : invalid 'times' argument
In addition: Warning message:
In as.vector(data) : NAs introduced by coercion
Here's another example:
> library(orthopolynom)
> hermite <-
2008 Jan 07
2
S3 vs S4 for a simple package
I am writing a package and need to decide whether to use S3 or S4.
I have a single class, "multipol"; this needs methods for "[" and "[<-"
and I also need a print (or show) method and methods for arithmetic +-
*/^.
In S4, an object of class "multipol" has one slot that holds an array.
Objects of class "multipol" require specific arithmetic
2006 Mar 29
2
bivariate case in Local Polynomials regression
Hi:
I am using the package "KernSmooth" to do the local polynomial regression. However, it seems the function "locpoly" can only deal with univariate covaraite. I wonder is there any kernel smoothing package in R can deal with bivariate covariates? I also checked the package "lcofit" in which function "lcofit" can indeed deal with bivariate case. The
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
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, Student抯 t, Inverse
gamma and Fisher抯 F distribution?
Thank you in advance!
David
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2010 Sep 21
1
partial dbRDA or CCA with two distance objects in Vegan.
I am trying to use the cca/rda/capscale functions in vegan to analyse
genetic distance data ( provided as a dist object calculated using
dist.genpop in package adegenet) with geographic distance partialled out
( provided as a distance object using dist function in veganthis method
is attempting to follow the method used by Geffen et al 2004 as
suggested by Legendre and . FORTIN (2010).
I
2008 Mar 27
2
assistance with RDAtest beta version application
Pierre Legendre has developed a beta version of a new redundancy analysis package called RdaTest that is available on his web page at the Universit® de Montréal. The test example that is included with the package is based on the example provided in his book (Numerical Ecology, Chapter 11 (Legendre & Legendre 1998))
I have downloaded the package and am attempting to run it so that I might
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)
2007 Feb 12
1
How to get the polynomials out of poly()
Hi Folks!
Im using the function poly to generate orthogonal polynomials, but Id like
to see the actual polynomials so that I could convert it to a polynomial
in my original variable. Is that possible and if so how do I do it?
/E
2004 Jun 23
0
chronological clustering
Does anybody know of any R functions to perform chronological clustering
as explained in:
Legendre, P., S. Dallot & L. Legendre. 1985. Succession of species
within a community: chronological clustering, with applications to
marine and freshwater zooplankton. American Naturalist 125: 257-288.
http://www.fas.umontreal.ca/BIOL/legendre/reprints/succession_of_species.pdf
Thanks,
Angel
2007 Apr 30
0
Intercept Coefficient in a Model with Orthogonal Polynomials
This very likely falls in the category of an unexpected result due to
user ignorance. I generated the following data:
time <- 0:10
set.seed(4302007)
y <- 268 + -9*time + .4*(time^2) + rnorm(11, 0, .1)
I then fit models using both orthogonal and raw polynomials:
fit1 <- lm(y ~ poly(time, 2))
fit2 <- lm(y ~ poly(time, degree=2, raw=TRUE))
> predict(fit1, data.frame(time =
2002 Oct 08
2
Orthogonal Polynomials
Looking to the wonderful statistical advice that this group can offer.
In behavioral science applications of stats, we are often introduced to
coefficients for orthogonal polynomials that are nice integers. For
instance, Kirk's experimental design book presents the following
coefficients for p=4:
Linear -3 -1 1 3
Quadratic 1 -1 -1 1
Cubic -1 3 -3 1
In R orthogonal