Displaying 20 results from an estimated 4000 matches similar to: "CART and the `tree' contrib package"
2000 Mar 31
2
linear models
Dear R users,
I have a couple of linear model related questions.
1) How do I produce a fixed effect linear model using lme? I saw somewhere
(this may be Splus documentation since I use Splus and R interchangeably)
that using lme(...,random= ~ -1 | groups,...) works, but it gives the same
as lme(...,random= ~ 1 | groups,...), ie. fits a random effect intercept
term.
The reason why I want to do
2006 Oct 21
2
problem with mode of marginal distriubtion of rdirichlet{gtools}
Hi all,
I have a problem using rdirichlet{gtools}.
For Dir( a1, a2, ..., a_n), its mode can be found at $( a_i -1)/ (
\sum_{i}a_i - n)$;
The means are $a_i / (\sum_{i} a_i ) $;
I tried to study the above properties using rdirichlet from gtools. The code
are:
##############
library(gtools)
alpha = c(1,3,9) #totoal=13
mean.expect = c(1/13, 3/13, 9/13)
mode.expect = c(0, 2/10, 8/10) #
2013 Jul 02
0
Optimización MINLP
Muy buenas,
Tengo la siguiente duda/problema,
He optimizado con éxito un problema de este tipo:
\sum f(x_i)
donde f es una curva exponencial (función no lineal)
sujeto a:
a_i < x_i < b_i
y
\sum f(x_i) < Presupuesto
Vamos, es repartir un presupuesto forzando a que inviertas como poco a_i y
como mucho b_i para cada i
Esto lo hecho correctamente usando el paquete:
2003 Jul 09
2
CFP: CART Data Mining Conference 2004
Apologies for cross posting....
---------------------------------------------------------------------
CART Data Mining'04: First International CART(R) Conferences
Focusing on the Data Mining technology of
Leo Breiman, Jerome Friedman, Richard Olshen, Charles Stone
(CART, MARS(R), TreeNet(tm), PRIM(tm)...)
First Call For submissions
2002 Sep 25
5
CART vs. Random Forest
According to Dr. Breiman, the RF should be more accurate
method than a single tree. However, the performance of each
method seems to depend on the proprotion of outcome variable
in my case. My data set is a typical classification problem
(predict bad guys). When I ran both of them with different
proportion of outcome variables(there's a criterion to measure
the degree of bad behavior), I
2008 Jul 21
2
CART and CHAID
Can I say that RPART is a modified algo of CART and PARTY a modified of
CHAID?
Thanks.
----
Chua Siang Li
Consultant - Operations Research
Acceval Pte Ltd
Tel: 6297 8740
Email: siang.li.chua at acceval-intl.com
Website: www.acceval-intl.com
This message and any attachments (the "message"...{{dropped:12}}
2002 Aug 20
0
Re: SVM questions
>
> So i guess from your prev. email the svmModel$coefs correspond to the
> "Alpha" .
yes (times the sign of y!).
>
> Why do I see three columns in the coefs?( Is this the number of classes -1
> = Numbe of hyperplanes)
yes, but in a packed format which is not trivial.
I attach some explanation I sent to R-help some time ago (the guy wanted
to write his own
2002 Aug 12
0
help with pseudo-random numbers
Dear People,
I have a vexing problem related to pseudo-random number generation, and
would appreciate any help and advice. This problem is not directly related
to R, and the only reason I am posting it to this list is that my
implementation is using R. Let me describe my problem by giving an
example, that is close to what I am trying to do.
Suppose we are given a stream of pseudo-random numbers,
2004 Feb 01
2
CART: rapart vs bagging
Hi,
Is here anyone knows the difference between rapart and bagging when grow a
CART tree?
Thanks
Qin
2010 Aug 24
1
Constrained non-linear optimisation
I'm relatively new to R, but I'm attempting to do a non-linear maximum
likelihood estimation (mle) in R, with the added problem that I have a
non-linear constraint.
The basic problem is linear in the parameters (a_i) and has only one
non-linear component, b, with the problem being linear when b = 0 and
non-linear otherwise. Furthermore, f(a_i) <= b <= g(a_i) for some
(simple) f
2004 Feb 09
0
CART Data Mining 2004 Conference, San Francisco, SCHEDULE information
Apologies for cross posting
CART Data Mining 2004, San Francisco, March 22-24, 2004
Below are links for the registration and the
latest scheduling information. Please note that you can register with an early-bird
discount if you register NOW and write the words "SCHEDULE" on your
registration form.
Homepage: http://www.cartdatamining.com
Detailed Conference Schedule:
2012 Oct 18
7
summation coding
I would like to code the following in R: a1(b1+b2+b3) + a2(b1+b3+b4) +
a3(b1+b2+b4) + a4(b1+b2+b3)
or in summation notation: sum_{i=1, j\neq i}^{4} a_i * b_i
I realise this is the same as: sum_{i=1, j=1}^{4} a_i * b_i - sum_{i=j} a_i
* b_i
would appreciate some help.
Thank you.
--
View this message in context: http://r.789695.n4.nabble.com/summation-coding-tp4646678.html
Sent from the R
2003 Feb 19
4
fitting a curve according to a custom loss function
Dear R-Users,
I need to find a smooth function f() and coefficients a_i that give the best
fit to
y ~ a_0 + a_1*f(x_1) + a_2*f(x_2)
Note that it is the same non-linear transformation f() that is applied to
both x_1 and x_2.
So my first question is how can I do it in R?
A more general question is this: suppose I have a utility function U(a_i,
f()), where f() is say a spline. Is there a general
2008 Aug 11
3
R-help? how to take difference in next two elements
Hi,
I'd like to take difference for a sequence a between a_i and a_i-2, for
instance,
a<-c(2,3,4,8,1)
I need (2, 5, -3) as a result. If not using a for loop, can anyone help me?
Thanks a lot.
Dot
--
View this message in context: http://www.nabble.com/R-help--how-to-take-difference-in-next-two-elements-tp18927968p18927968.html
Sent from the R help mailing list archive at Nabble.com.
2013 Mar 22
1
Integration of vector syntax unknown
Hello,
I'm very new to using R, but I was told it could do what I want. I'm not sure how best to enter the information but here goes...
I'm trying to transfer the following integral into R to solve for ln(gamma_1), on the left, for multiple instances of gamma_i and variable N_i.
gamma_i is, for example, (0, 0.03012048, 0.05000000, 0.19200000, 0.44000000, 0.62566845)
N_i (N_1 or
2004 Apr 18
2
lm with data=(means,sds,ns)
Hi Folks,
I am dealing with data which have been presented as
at each x_i, mean m_i of the y-values at x_i,
sd s_i of the y-values at x_i
number n_i of the y-values at x_i
and I want to linearly regress y on x.
There does not seem to be an option to 'lm' which can
deal with such data directly, though the regression
problem could be algebraically
2010 Feb 06
1
Canberra distance
Hi the list,
According to what I know, the Canberra distance between X et Y is : sum[
(|x_i - y_i|) / (|x_i|+|y_i|) ] (with | | denoting the function
'absolute value')
In the source code of the canberra distance in the file distance.c, we
find :
sum = fabs(x[i1] + x[i2]);
diff = fabs(x[i1] - x[i2]);
dev = diff/sum;
which correspond to the formula : sum[ (|x_i - y_i|) /
2000 Sep 14
0
modifying Openssh config script for KTH-KRB (fwd)
Dear OpenSSH developers,
Hi, taking the liberty of sending this to your mailing list in the hope
someone will be able to help. The KTH version of Kerberos 4 was the only
one I was able to find.
In case you don't want to look at all the stuff below, the situation is
briefly that I am trying to compile openssh with kerberos 4 support, which
it apparently has. However, it can't find krb.h,
2010 Nov 28
1
faster base::sequence
Hello,
Based on yesterday's R-help thread (help: program efficiency), and
following Bill's suggestions, it appeared that sequence:
> sequence
function (nvec)
unlist(lapply(nvec, seq_len))
<environment: namespace:base>
could benefit from being written in C to avoid unnecessary memory
allocations.
I made this version using inline:
require( inline )
sequence_c <- local( {
2001 Feb 07
1
Re: failed rpm installation of R 1.2-1 (fwd)
On Wed, 7 Feb 2001, Faheem Mitha wrote:
> Dear Albrecht,
>
> Just sent the following message out to r-help. Have you any idea what this
> problem could be?
>
> Sincerely, Faheem Mitha.
>
> ---------- Forwarded message ----------
> Date: Wed, 7 Feb 2001 00:04:35 -0500 (EST)
> From: Faheem Mitha <faheem at email.unc.edu>
> To: