Displaying 20 results from an estimated 10000 matches similar to: "Fitting parabolic function to data"
2008 Aug 21
1
Parabolic cylinder function
Dear all,
I need your advice since I am looking for an implementation of the parabolic
cylinder function in R. I found implemantations of the hypergemetric
functions (the Whittaker and the confluent hypogeometric functions) in the
package fAsianOptions but the parabolic cylinder function was unfortunately
not there. Do you know of such implementation?
Thank you very much for your advice.
2011 Apr 01
5
MySql Versus R
Dear R Users,
I use for my data crunching a combination of MySQL and GNU R. I have
to handle huge/ middle seized data which is stored in a MySql
database, R executes a SQL command to fetch the data and does the
plotting with the build in R plotting functions.
The (low level) calculations like summing, dividing, grouping, sorting
etc. can be done either with the sql command on the MySQL side or
2011 Sep 13
2
Convert "RDX" and "RDB" to ASCII format?
Dear R users and experts,
I need to modify an exisiting R function from a package. The function/
variable is inside a namespace and I have problems accessing it.
I only need to get access to to corresponding sourcecode. I localised
the "RDX" and "RDB" files. But it seems to be a binary format.
How can I convert it to an ASCII format to open and extract the code
from a text
2011 Jul 17
1
ODBC MySql DB: sqlQuery empty
Dear R Beginners, Experts and Users,
I already asked this question on the R-sig-DB mailing list, but sadly
didn't got a reply :-( .
Keeping fingers crossed that I have more luck on the main R mailinglist :) .
I'm trying to connect to a MySQl database via Gnu R using the RODBC
interface. The conenction workes but I get an empty result string.
Gnu R and the MySql DB are running on a 64 bit
2011 May 02
2
easy way to do a 2-D fit to an array of data?
Hi,
I've got a matrix, Z, of values representing (as it happens) optical
power at each pixel location. Since I know in advance I've got a
single, convex peak, I would like to do a 2D parabolic fit of the form
Z = poly((x+y),2) where x and y are the x,y coordinates of each pixel
(or equivalently, the row, column numbers).
Is there an R function that lets me easily implement that?
2001 Jul 06
1
fit simple surface to 2d data?
I have an array of floating-point measurements on a square (5 by 5) 2d grid.
The data are nominally constant, and somewhat noisy.
I need to find any significant spatial trend, e.g. bigger on the
left, bigger in the middle, etc. I have many thousands of these data sets
that need to be scanned for 'interesting' spatial variations, selecting the
datasets that are beyond some criterion of
2011 Feb 24
3
problem in for loop
Hi all.
I was having some trouble with a for loop and I found the problem is the
following.
Does anyone have some idea why I got the following R result? Since mone
is equal to 3, why
mu1 only have 2 components?
library(MASS)
> p0 <- seq(0.1, 0.9,by=0.1)
> m <- 10
>
>
> p0 <- p0[7]
>
> ## data generation
>
> mzero <- p0*m
> mone <- m-mzero
>
2006 Sep 27
1
PDE
Dear all,
Does any know how to solve PDE with R? The archive list refers to the
use of ODE if PDE are parabolic. I am not a mathematician and this does
not mean anything for me!
help would be very appreciated.
Many thanks
--
___________________________________________________
Christophe NGUYEN
UMR 1220 INRA-ENITAB
Transfert sol-plante et cycle des ?l?ments min?raux
dans les ?cosyst?mes
2005 Jan 17
1
Re: Any interest in a Canadian Asterisk
Quoting asterisk-users-request@lists.digium.com:
> > Would it be considered trolling to start a thread on Cleaning Maple
> > Syrup off of Dial Pads, or Wiring your Moose for Wi-Fi?
>
> Let's not forget the weekly "tooques and telephony" segment, and a
> review of
> the best block heaters for your wi-fi fones.
>
Oh, we're gonna have a good time next
2012 Jun 13
3
How to plot linear, cubic and quadratic fitting curve in a figure?
Hi R experts,
Could you please help me to fit a linear, cubic and quadratic curve in a figure? I was trying to show all these three fitting curves with different colour in one figure.
I spent substantial time to figure it out, but I could not.
I have given here a example and what I did for linear, but no idea for cubic and quadratic fitting curve
> dput(test)
structure(list(sp = c(4L, 5L,
2009 Jun 16
2
Statistically detecting thresholds...
Rers:
I have some ecological data (stream velocity vs. % cover of submerged
weeds) that shows strong evidence of a thresholding step-function, e.g.
below some velocity, % cover ranges from 0% to 100% (with no apparent
relationship to velocity within this range of velocities), but above a
certain "threshold" velocity, the % cover does not appear to exceed,
say, 10%. There are good
2017 Jul 13
3
How to formulate quadratic function with interaction terms for the PLS fitting model?
I have two ideas about it.
1-
i) Entering variables in quadratic form is done with the command I
(variable ^ 2) -
plsr (octane ~ NIR + I (nir ^ 2), ncomp = 10, data = gasTrain, validation =
"LOO"
You could also use a new variable NIR_sq <- (NIR) ^ 2
ii) To insert a square variable, use syntax I (x ^ 2) - it is very
important to insert I before the parentheses.
iii) If you want to
2017 Jul 13
0
How to formulate quadratic function with interaction terms for the PLS fitting model?
Below.
-- Bert
Bert Gunter
On Thu, Jul 13, 2017 at 3:07 AM, Luigi Biagini <luigi.biagini at gmail.com> wrote:
> I have two ideas about it.
>
> 1-
> i) Entering variables in quadratic form is done with the command I
> (variable ^ 2) -
> plsr (octane ~ NIR + I (nir ^ 2), ncomp = 10, data = gasTrain, validation =
> "LOO"
> You could also use a new variable
2001 Mar 09
0
Fitting automatically empirical data
Hi,
I'm using R to find esplicit functions fitting set of data.
The data contains about 30 points, which have different weights (number
of cases represented from the point).
I plot the points, choose "by eye" a function made with exp or arctg or
polinomial and use nlm to minimaze the root mean error with correct the
weights.
For Example:
Err <- function(p)
sum((weight*(y
2017 Jul 13
2
Quadratic function with interaction terms for the PLS fitting model?
Dear all,
I am using the pls package of R to perform partial least square on a set of
multivariate data. Instead of fitting a linear model, I want to fit my
data with a quadratic function with interaction terms. But I am not sure
how. I will use an example to illustrate my problem:
Following the example in the PLS manual:
## Read data
data(gasoline)
gasTrain <- gasoline[1:50,]
## Perform
2017 Jul 16
2
How to formulate quadratic function with interaction terms for the PLS fitting model?
> On Jul 13, 2017, at 7:43 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote:
>
> Below.
>
> -- Bert
> Bert Gunter
>
>
>
> On Thu, Jul 13, 2017 at 3:07 AM, Luigi Biagini <luigi.biagini at gmail.com> wrote:
>> I have two ideas about it.
>>
>> 1-
>> i) Entering variables in quadratic form is done with the command I
>>
2007 Oct 01
3
Apparently Conflicting Results with coxph
Dear List:
I have a data frame prepared in the couting process style for including
a binary time-dependent covariate. The first few rows look like this.
PtNo Start End Status Imp
1 1 0 608.0 0 0
2 2 0 513.0 0 0
3 2 513 887.0 0 1
4 3 0 57.0 0 0
5 3 57 604.0 0 1
6 4 0 150.0 1 0
The outcome
2017 Jul 16
0
How to formulate quadratic function with interaction terms for the PLS fitting model?
??
If I haven't misunderstood, they are completely different!
1) NIR must be a matrix, or poly(NIR,...) will fail.
2) Due to the previously identified bug in poly, degree must be
explicitly given as poly(NIR, degree =2,raw = TRUE).
Now consider the following example:
> df <-matrix(runif(60),ncol=3)
> y <- runif(20)
> mdl1 <-lm(y~df*I(df^2))
> mdl2
2017 Jul 13
0
Quadratic function with interaction terms for the PLS fitting model?
> On Jul 12, 2017, at 6:58 PM, Ng, Kelvin Sai-cheong <kscng at connect.hku.hk> wrote:
>
> Dear all,
>
> I am using the pls package of R to perform partial least square on a set of
> multivariate data. Instead of fitting a linear model, I want to fit my
> data with a quadratic function with interaction terms. But I am not sure
> how. I will use an example to
2010 Dec 22
2
Fitting a Triangular Distribution to Bivariate Data
Hello,
I have some xy data which clearly shows a non-monotonic, peaked
triangular trend. You can get an idea of what it looks like with:
x<-1:20
y<-c(2*x[1:10]+1,-2*x[11:20]+42)
I've tried fitting a quadratic, but it just doesn't the data-structure
with the break point adequately. Is there anyway to fit a triangular
or 'tent' function to my data in R?
Some sample code