Displaying 20 results from an estimated 1000 matches similar to: "geodesic distance"
2006 Aug 03
0
geodesic distance (solved)
I found the answer to my problem.
stefano
2006 Jan 19
1
Minimizing mahalanobis distance to negative orthant
Hi
I have the following problem: given x (px1) and S (pXp positive definite), find y such that y_i<=0 (i=1..p) minimizing the
mahalanobis distance (x-y)'S^{-1}(x-y).
Has anyone worked on this problem? Tips or R code would be appreciated.
David
____________________
David Edwards
Principal scientist
Biostatistics
Novo Nordisk A/S
Novo Allé
2880 Bagsvaerd
Denmark
+45 4444 8888 (phone)
2013 Feb 25
3
Empirical Bayes Estimator for Poisson-Gamma Parameters
Dear Sir/Madam,
I apologize for any cross-posting. I got a simple question, which I thought
the R list may help me to find an answer. Suppose we have Y_1, Y_2, ., Y_n ~
Poisson (Lambda_i) and Lambda_i ~Gamma(alpha_i, beta_i). Empirical Bayes
Estimator for hyper-parameters of the gamma distr, i.e. (alpha_t, beta_t)
are needed.
y=c(12,5,17,14)
n=4
What about a Hierarchal B ayes
2008 Apr 12
2
nonlinear curve fitting on a torus
Dear R users.
I have data observed on the surface of a torus, and
am trying to fit the nonlinear regression using
the geodesic equation on a torus. Could anyone give
me a helpful advise on this problem? I would
definitely appreicate your reply.
Sincerely,
SUNGSU KIM
[[alternative HTML version deleted]]
2011 Mar 14
1
Math characters in column heading using latex() in Hmisc
Hi Everybody
I want to print a latex table containing math characters in the column
heading
These are the formulae I want to use as column headings. It prints OK from
TeX
$\sum_{i}\sum_{j}C_{P,i,j,y}\times\mathit{FC}_{i}$, $XU_{alt,y}$, $n$,
$\bar{C}_{P,y}$
My plan was to create a character vector with these and later rbind the
values to them. When I create the vector like:
2003 Jul 10
1
The question is on Symmetry model for square table.
Please help,
I tried a program on S-plus, and it worked. Also I tried the same
program on R but not worked. Here is the programme. I put it in a
function form. The model and assumption are at the bottom.
where
counts<-c(22,2,2,0,5,7,14,0,0,2,36,0,0,1,17,10)
which is name.data, i is row size and j is the column size.
symmetry
function(i, j, name.data)
{
row <- (c(1:i))
col <-
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
2010 Nov 19
2
Calculating distance between longitude,latitude of 2 points
Hi all,
I would like to know a way of calculating the distance between 2 points when
I already have the longitude and latitude of the points.
For example :
Point 1 : 52? 9'54.00"N 4?25'8.40"E
Point 2 : 52?27'46.80"N 4?33'18.00"E
Distance between point 1 and point in km ....
Is there any functions already available for this ?
Any help will be much
2009 May 01
2
Double summation limits
Dear R experts
I need to write a function that incorporates double summation, the problem
being that the upper limit of the second summation is the index of the first
summation, i.e:
sum_{j=0}^{x} sum_{i=0}^{j} choose(i+j, i)
where x variable or constant, doesn't matter.
The following code obviously doesn't work:
f=function(x) {j=0:x; i=0:j; sum( choose(i+j,i) ) }
Can you help?
Thanks
2009 Oct 17
2
Recommendation on a probability textbook (conditional probability)
I need to refresh my memory on Probability Theory, especially on
conditional probability. In particular, I want to solve the following
two problems. Can somebody point me some good books on Probability
Theory? Thank you!
1. Z=X+Y, where X and Y are independent random variables and their
distributions are known.
Now, I want to compute E(X | Z = z).
2.Suppose that I have $I \times J$ random number
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) #
2005 Jun 14
1
within and between subject calculation
Dear helpers in this forum,
I have the following question:
Suppose I have the following data set:
id x y
023 1 2
023 2 5
023 4 6
023 5 7
412 2 5
412 3 4
412 4 6
412 7 9
220 5 7
220 4 8
220 9 8
......
and i want to calculate sum_{i=1}^k
sum_{j=1}^{n_i}x_{ij}*y_{ij}
is there a simple way to do this within and between
subject summation in R?
2009 Mar 25
1
Confusion about ecdf
Hi,
I'm bit confused about ecdf (read the help files but still not sure about
this). I have an analytical expression for the pdf, but want to get the
empirical cdf. How do I use this analytical expression with ecdf?
If this helps make it concrete, the pdf is:
f(u) = \sum_{t = 1}^T 1/n_t \sum_{i = 1}^{n_t} 1/w K((u - u_{it})/w)
where K = kernel density estimator, w = weights, and u_{it} =
2009 Nov 21
1
Changing coordenates
Hi everybody:
Does anyone know how I can change geodesic coordenates into UTM ones?
Thanks in advance for your cooperation,
Jimmy M.
_________________________________________________________________
Bing brings you maps, menus, and reviews organized in one place.
a=TEXT_MFESRP_Local_MapsMenu_Resturants_1x1
[[alternative HTML version deleted]]
2010 Nov 15
1
Proportional hazard model with weibull baseline hazard
Dear R-users,
I would like to fit a fully parametric proportional hazard model with a
weibull baseline hazard and a logit link function. This is, the hazard
function is: lambda_i (t) = lambda_0 (t) psi (x_i* beta)
where lambda_0 is a weibull distribution and psi a logistic distribution.
Does someone know a package and/or function on R to do this?
Thanks.
--
M.L. Avendaño
[[alternative HTML
2005 Jun 15
2
need help on computing double summation
Dear helpers in this forum,
This is a clarified version of my previous
questions in this forum. I really need your generous
help on this issue.
> Suppose I have the following data set:
>
> id x y
> 023 1 2
> 023 2 5
> 023 4 6
> 023 5 7
> 412 2 5
> 412 3 4
> 412 4 6
> 412 7 9
> 220 5 7
> 220 4 8
> 220 9 8
> ......
>
Now I want to compute the
2006 Dec 08
1
MAXIMIZATION WITH CONSTRAINTS
Dear R users,
I?m a graduate students and in my master thesis I must
obtain the values of the parameters x_i which maximize this
Multinomial log?likelihood function
log(n!)-sum_{i=1]^4 log(n_i!)+sum_
{i=1}^4 n_i log(x_i)
under the following constraints:
a) sum_i x_i=1,
x_i>=0,
b) x_1<=x_2+x_3+x_4
c)x_2<=x_3+x_4
I have been using the
?ConstrOptim? R-function with the instructions
2008 Mar 27
1
functions
I wrote some functions for multiway CANDECOMP, i.e. for least
squares fitting of
a_{i_1\cdots i_m}\approx\sum_{s=1}^p x^1_{i_1s}x^1_{i_1s}\cdots
x^m_{i_ms}
with arrays of arbitrary dimension. Reminded me of the good old APL
days. I could not find this in the archives, but if it's already there,
I would appreciate if someone let me know.
2018 Apr 18
2
[Bug 106120] New: Hang in XScreenSaver
https://bugs.freedesktop.org/show_bug.cgi?id=106120
Bug ID: 106120
Summary: Hang in XScreenSaver
Product: xorg
Version: git
Hardware: Other
OS: All
Status: NEW
Severity: normal
Priority: medium
Component: Driver/nouveau
Assignee: nouveau at lists.freedesktop.org
2009 May 18
8
Simple plotting errors
Dear R Users,
I have 12 data frames, each of 12 rows and 2 columns.
e.g. FeketeJAN
MEAN SUM_
AMAZON 144.4997874 68348.4
NILE 5.4701955 1394.9
CONGO 71.3670036 21196.0
MISSISSIPPI 18.9273250 6511.0
AMUR 1.8426874 466.2
PARANA 58.3835497 13486.6
YENISEI 1.4668313 592.6
OB 1.4239179 559.6
LENA 0.9342164