Displaying 20 results from an estimated 900 matches similar to: "solving equation system"
2010 Mar 11
4
help about solving two equations
I have two matrix s1 and s2, each of them is 1000*1.
and I have two equations:
digamma(p)-digamma(p+q)=s1,
digamma(q)-digamma(p+q)=s2,
and I want to sovle these two equations to get the value of x and y, which are also two 1000*1 matrices.
I write a program like this:
f <- function(x) {
p<- x[1]; q <- x[2];
((digamma(p)-digamma(p+q)-s1[2,]) )^2 +((digamma(q)-digamma(p+q)-s2[2,]) )^2
2004 Feb 29
1
digamma with negative arguments (PR#6626)
Full_Name: Chanseok Park
Version: 1.8.1
OS: linux-gnu
Submission from: (NULL) (130.127.112.183)
digamma with any negative value does not give a right answer.
It gives -1.797693e+308 for any negative arguments.
For example, digamma(-1.1) gives -1.797693e+308.
The right answer should be 10.15416
This bug can be easily fixed by using the following digamma identity.
digamma(x) = digamma(1-x) -
2007 Feb 09
6
syslinux-3.36-pre8 feedback
Tested floppy boot on two machines (one PII 350, one 486DX4)
Floppy boot with syslinux is very very slow, more than 18 mn to boot a linux
kernel from floppy on the 2 machines.
Tested with 3 different disquettes that were know to work, boot is reached
after this very long time.
Noise from floppy head make think floppy wait approximatly one minute
between each read.
No problem with pxe boot with
2008 Jan 27
2
Likelihood optimization numerically
Dear List,
I am not sure how should i optimize a log-likelihood numerically:
Here is a Text book example from Statistical Inference by George Casella, 2nd
Edition Casella and Berger, Roger L. Berger (2002, pp. 355, ex. 7.4 # 7.2.b):
data = x = c(20.0, 23.9, 20.9, 23.8, 25.0, 24.0, 21.7, 23.8, 22.8, 23.1, 23.1, 23.5, 23.0, 23.0)
n <- length(x)
# likelihood from a 2 parameter Gamma(alpha,
2010 Jan 04
1
polygamma or Hurwitz zeta function
Hi,
Is there any R library that is capable of handling polygamma function
(Hurwitz zeta function also works)? I am aware of digamma(0 and trigamma(),
but could not find more advanced versions.
I'd appreciate any help.
Hakan Demirtas
2007 Oct 14
1
Extending deriv3()
Hello,
I was wondering if the functions deriv3(), deriv() etc. could be extended
to handle psigamma() and its special cases (digamma(), trigamma()
etc.). From the error message it seems that 'psigamma' needs to be
added to the derivatives table.
This might be easy since psigamma() has a deriv argument.
Additionally, this error message is also obtained when requesting for
the Hessian of
2003 Sep 09
3
samba3: need to wait 3 minutes before login
Hi,
at our local computer pool in the school we've a samba3
server and about 40 winnt-4.0 workstations. the main
problem is, that the workstations have to wait for
about 3 minutes after they started, before a user can
login. in other words: the computer starts and if you
try to login then immediatly you'll get "domain manos
not available" or something like this. but if you wait
2009 Jun 03
2
problem with uniroot
Hi R-users,I'm trying to solve a non linear equation, to find the degrees of
freedom of a mixture of t student. I'm sure i wrote the minimization
equation in the right way, but when i try to run the EM algorithm to
estimate the parameters of the mixture, the following error will appear:
Error in uniroot(function(z) log(z/2) - digamma(z/2) + 1 - log((z + d)/2) +
:
f() values at end
2009 May 16
1
maxLik pakage
Hi all;
I recently have been used 'maxLik' function for maximizing G2StNV178 function with gradient function gradlik; for receiving this goal, I write the following program; but I have been seen an error in calling gradient function;
The maxLik function can't enter gradlik function (definition of gradient function); I guess my mistake is in line ******** ,that the vector ‘h’ is
2005 Jan 10
4
Graphical table in R
I would like R to produce some tabulated data in a graphical output. When
I say tabulated data, what I mean is a table with rows and columns. This
would be useful when reading in a big file, performing some analysis on
it, and then wanting to display the results as a table.
Something like
plot(x,...)
where x is a matrix
For example, the result could look (approximatly) like...
2006 Feb 09
1
TDM2400P FXS Only vs. T1/E1 to FXS Channel Banks
Hello All,
I'm looking to get some feedback on which solution of providing FXS is
going to have the best results with faxing. I'm only looking to see what
method is going to provide the best digitization into Asterisk, not for
transmission from Asterisk to else where. Any recommendations of
specific channel banks are welcome. I will need to provide approximatly
216 FXS Ports and need
2002 Sep 11
2
WG: troubles deleting lots of files
> hello,
>
> i encountered a very strange problem and hope that someone out there knows a solution. that is, when i'm deleting several tousand files with a batch script on a samba share, windows says: "the system could not find the path specified" and deletes just approximatly one third of the files. this only occures if i'm delete explicitly from a dos shell using
2007 Jul 21
1
Gamma MLE
Hello,
I was asked to try the following code on R,
gamma.mles
function (xx,shape0,rate0)
{
n<- length(xx)
xbar<- mean(xx)
logxbar<- mean(log(xx))
theta<-c(shape0,rate0)
repeat {
theta0<- theta
shape<- theta0[1]
rate<- theta0[2]
S<- n*matrix(c(log(rate)-digamma(shape)+logxbar,shape/rate-xbar),ncol=1)
I<- n*matrix(c(trigamma(shape),-1/rate,-1/rate,shape/rate^2),ncol=2)
2010 May 05
1
testInstalledBasic question
Hi,
I'm currently in the process of writing an R-installation SOP for my
company. As part of that process I'm using the recommendations from the 'R
Installation and Administration' document, section 3.2, "Testing an
installation". This is done on an XP machine, using the latest binary of
2.11.0.
The binary is downloaded and then installed from the installer. I then
2011 Dec 17
2
Problem with reproducing log likelihood estimated with ghyp package
I was playing around with the ghyp package and simulated series of
t-distributed variables when suddenly i was not able to reproduce the log
likelihood values reported by the package. When trying to reproduce the
likelihood values, I summed the log(dt(x,v)) values and it worked with some
simulated series but not all.
Is there any obvious flaws with this script?
library("ghyp")
1998 Nov 27
1
Time to connect
Greetings Fellow Sambaiites!
I have a small problem that I haven't seen addressed in any of the
forums (have searched the net to no avail!).
I have a small 100 mbit network................using Samba 1.9.18p10
on a Slack box as the PDC.
When I initially look in the NN on any Win95,98 and NT boxes, the
Samba box appears...................when I try to browse the Samba
shares on the
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.
2006 Oct 30
1
psigamma derivative
Hello,
I am trying to find a hessian matrix that
involves log(gamma(1/p)) second derivative, p being one of the parameters
of the function. I am using a function "deriv" with the hessian=TRUE
option, but psigamma is not on the list of derivative functions.
I know that it is possible to use 'psigamma(p,deriv)', but it doesn't work
with 1/p. Does anybody can help with this?
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
2007 Oct 13
2
the use of the .C function
Dear All,
could someone please shed some light on the use of the .C or .Fortran function:
I am trying load and running on R the following function
// psi.cpp -- psi function for real arguments.
// Algorithms and coefficient values from "Computation of Special
// Functions", Zhang and Jin, John Wiley and Sons, 1996.
//
// (C) 2003, C. Bond. All rights reserved.
//
//