Displaying 20 results from an estimated 662 matches for "polynomially".
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polynomial
2004 Dec 03
3
Computing the minimal polynomial or, at least, its degree
Hi,
I would like to know whether there exist algorithms to compute the
coefficients or, at least, the degree of the minimal polynomial of a square
matrix A (over the field of complex numbers)? I don't know whether this
would require symbolic computation. If not, has any of the algorithms been
implemented in R?
Thanks very much,
Ravi.
P.S. Just for the sake of completeness, a
2010 Oct 05
2
Using as.polynomial() over a matrix
Hello All
First - a warning. I'm not very R or programming savvy.
I am trying to do something without much luck, and have scoured help-pages, but nothing has come up. Here it is:
I have a matrix (m) of approx 40,000 rows and 3 columns, filled with numbers.
I would like to convert the contents of this matrix into another matrix (m_p), where the numbers of (m) have been coerced into a
2009 Jan 11
4
How to get solution of following polynomial?
Hi, I want find all roots for the following polynomial :
a <- c(-0.07, 0.17); b <- c(1, -4); cc <- matrix(c(0.24, 0.00, -0.08,
-0.31), 2); d <- matrix(c(0, 0, -0.13, -0.37), 2); e <- matrix(c(0.2, 0,
-0.06, -0.34), 2)
A1 <- diag(2) + a %*% t(b) + cc; A2 <- -cc + d; A3 <- -d + e; A4 <- -e
fn <- function(z)
{
y <- diag(2) - A1*z - A2*z^2 - A3*z^3 - A4*z^4
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
[[alternative HTML version deleted]]
2003 Nov 03
1
svm in e1071 package: polynomial vs linear kernel
I am trying to understand what is the difference between linear and
polynomial kernel:
linear: u'*v
polynomial: (gamma*u'*v + coef0)^degree
It would seem that polynomial kernel with gamma = 1; coef0 = 0 and degree
= 1
should be identical to linear kernel, however it gives me significantly
different results for very simple
data set, with linear kernel
2007 Aug 15
1
Polynomial fitting
Hi everybody!
I'm looking some way to do in R a polynomial fit, say like polyfit
function of Octave/MATLAB.
For who don't know, c = polyfit(x,y,m) finds the coefficients of a
polynomial p(x) of degree m that fits the data, p(x[i]) to y[i], in a
least squares sense. The result c is a vector of length m+1 containing
the polynomial coefficients in descending powers:
p(x) = c[1]*x^n +
2008 Jan 07
3
Polynomial fitting
I wonder how one in R can fit a 3rd degree polynomial to some data?
Say the data is:
y <- c(15.51, 12.44, 31.5, 21.5, 17.89, 27.09, 15.02, 13.43, 18.18, 11.32)
x <- seq(3.75, 6, 0.25)
And resulting degrees of polynomial are:
5.8007 -91.6339 472.1726 -774.2584
THanks in advance!
--
Jonas Malmros
Stockholm University
Stockholm, Sweden
2003 Apr 29
1
polynomial fitting
I'm trying to find a way to fit a polynomial of degree n in x and y to
a set of x, y, and z data that I have and obtain the coefficients for
the terms of the fitted polynomial. However, when I try to use the
surf.ls function I'm getting odd results.
> x <- seq(0, 10, length=50)
> y <- x
> f <- function (x, y) {x^2 + y}
> library(spatial)
> test <-
2013 Apr 27
2
Polynomial Regression and NA coefficients in R
Hey all,
I'm performing polynomial regression. I'm simulating x values using runif() and y values using a deterministic function of x and rnorm().
When I perform polynomial regression like this:
fit_poly <- lm(y ~ poly(x,11,raw = TRUE))
I get some NA coefficients. I think this is due to the high correlation between say x and x^2 if x is distributed uniformly on the unit interval
2011 Jul 07
1
Polynomial fitting
Hello,
i'm fairly familiar with R and use it every now and then for math related
tasks.
I have a simple non polynomial function that i would like to approximate
with a polynomial. I already looked into poly, but was unable to understand
what to do with it. So my problem is this. I can generate virtually any
number of datapoints and would like to find the coeffs a1, a2, ... up to a
given
2010 May 17
2
best polynomial approximation
Dear R-users,
I learned today that there exists an interesting topic in numerical
analysis names "best polynomial approximation" (BSA). Given a function
f the BSA of degree k, say pk, is the polynomial such that
pk=arginf sup(|f-pk|)
Although given some regularity condition of f, pk is unique, pk IS NOT
calculated with least square. A quick google tour show a rich field of
research
2009 Sep 28
2
Polynomial Fitting
Hello All,
This might seem elementary to everyone, but please bear with me. I've
just spent some time fitting poly functions to time series data in R
using lm() and predict(). I want to analyze the functions once I've
fit them to the various data I'm studying. However, after pulling the
first function into Octave (just by plotting the polynomial function
using fplot() over
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 [*]).
2004 May 06
5
Orthogonal Polynomial Regression Parameter Estimation
Dear all,
Can any one tell me how can i perform Orthogonal
Polynomial Regression parameter estimation in R?
--------------------------------------------
Here is an "Orthogonal Polynomial" Regression problem
collected from Draper, Smith(1981), page 269. Note
that only value of alpha0 (intercept term) and signs
of each estimate match with the result obtained from
coef(orth.fit). What
2011 Feb 02
2
unequally spaced factor levels orthogonal polynomial contrasts coefficients trend analysis
Hello [R]-help
I am trying to find
> a package where you can do ANOVA based trend analysis on grouped data
> using orthogonal polynomial contrasts coefficients, for unequally
> spaced factor levels. The closest hit I've had is from this web site:
>(http://webcache.googleusercontent.com/search?q=cache:xN4K_KGuYGcJ:www.datavis.ca/sasmac/orpoly.html+Orthogonal+polynomial
>l
but I
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
2006 Feb 22
1
Gram-Charlier series
Good day everyone,
I want to use the Gram-Charlier series expansion to model
some data. To do that, I need functions to:
1) Calculate 'n' moments from given data
2) Transform 'n' moments to 'n' central moments, or
3) Transform 'n' moments to 'n' cumulants
4) Calculate a number of Hermite polynomials
Are there R-functions to do any of the above?
2005 Jun 14
2
ordinary polynomial coefficients from orthogonal polynomials?
How can ordinary polynomial coefficients be calculated
from an orthogonal polynomial fit?
I'm trying to do something like find a,b,c,d from
lm(billions ~ a+b*decade+c*decade^2+d*decade^3)
but that gives: "Error in eval(expr, envir, enclos) :
Object "a" not found"
> decade <- c(1950, 1960, 1970, 1980, 1990)
> billions <- c(3.5, 5, 7.5, 13, 40)
> #
2002 Sep 24
4
print(), paste()
Hi,
Suppose I have the following lines at the end of a function:
answer <- c(2, 1, 0, 4, 5) # In fact, answer will be generate in my
# function
print(answer) # Print the answer
# Now, find the best fitted n degree polynomial
print(paste("The best fit is with", which.min(answer) - 1,
"-degree polynomial"))
this will return:
2024 Oct 10
0
Discriminant of a cubic polynomial
Dear Thomas,
Unfortunately, I do not know if any packages implement this functionality. Though, it is a topic that interests me.
Unlike the "classic discriminant", I prefer to work with the reduced polynomial. This "discriminant" is generalizable to a superset of Chebysev polynomials (which I called Cardano-polynomials).
x^3 - 3*c*x - 2*d = 0
x^5 - 5*c*x^3 + 5*c^2*x - 2*d =