Displaying 20 results from an estimated 2000 matches similar to: "Optimization"
2007 Jul 17
1
Optimization (MAX) with R
Dear all,
I need a suggest to obtain the max of this function:
Max x1*0.021986+x2*0.000964+x3*0.02913
with these conditions:
x1+x2+x3=1;
sqrt((x1*0.114434)^2+(x2*0.043966)^2+(x3*0.100031)^2)=0.04;
x1>=0;
x1<=1;
x2>=0;
x2<=1;
x3>=0;
x3<=1;
Any suggests ?
Thanks in advanced,
Massimiliano
Questo messaggio di posta elettronica contiene informazioni di carattere
2005 Jul 04
2
RESIDUALS IN THE AR TIME SERIES FUNCTION
Dear all,
It's possible to obtain the residuals with AR time series function.
Thanks in advance,
Massimiliano Talarico
Pianificazione Commerciale - Area Crm
Unicredit Xelion Banca S.p.A.
Via Pirelli 32 - 20124 Milano
Tel.: 02 67360 525
Fax: 02 67738 525
www.xelion.it
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2009 Jul 17
6
Solving two nonlinear equations with two knowns
Dear R users,
I have two nonlinear equations, f1(x1,x2)=0 and f2(x1,x2)=0. I try to use optim command by minimize f1^2+f2^2 to find x1 and x2. I found the optimal solution changes when I change initial values. How to solve this?
BTW, I also try to use grid searching. But I have no information on ranges of x1 and x2, respectively.
Any suggestion to solve this question?
Thanks,
Kate
2010 Nov 12
1
what's wrong with this 'length' in function?
Hi all,
I am having a trouble with this function I wrote
###################################################
p26=function(x,alpha){
# dummy variable
j=1
ci=matrix(ncol=2,nrow=3)
while (j<4){
if (j==2) {x=x+c(-1,1)*0.5}
ci[j,]=
x+qnorm(1-alpha/2)^2/2+
c(-1,1)*qnorm(1-alpha/2)*
sqrt(x+qnorm(1-alpha/2)^2/4)
j=j+1
if (j==3) { # exact
x=x-c(-1,1)*0.5
2004 Jan 28
5
Julian dates
Hi all,
I have problems with years of dates using "chron" package.
I don't understand why R by this istruction:
> dates("01/02/29",out.format="d/m/year")
[1] 02/Jan/2029
> dates("01/02/30",out.format="d/m/year")
[1] 02/Jan/1930
reads "29" as 2029
and "30" as 1930. How could I change to read "00" to
2012 Mar 31
3
Samba LDAP Failover
Hi,
I have a quite "simple" setup for a particular customer that loves
redundancy and failover.
PDC + BDC with LDAP Passwords on two 389-ds in multimaster node +
several samba member servers
Actually pointing singularly on both the systems everything works great.
As soon as I modify my passdb backend line from the single form to the
form containing both backends that is
from
passdb
2004 Nov 16
3
memory allocation
Dear sirs,
I'm using the Splancs package to compute standard errors of the estimates of a
spatio-temporal k function.
When I use as spatial and temporal distances too long vectors (respectively 60
and 80 entries) for a dataset of 1000 observations, R gives me the message
Error: cannot allocate vector of size 180000 Kb
Reached total allocation of 512 Mb.
I ran the function memory.size()
2011 Apr 27
1
paste function by INDICES
Dear all,
I have the following R dataframe:
set.seed(11)
(df <- data.frame(ID=rep(1:10,1:10),a=factor(sample(1:4,55,rep=T)) ))
where ID is an identification code.
I need to create a new variable "b" in which I would paste the full group
of "a" variable according to ID variable.
For example for ID=2 "b" should be 13, for ID=3 "b" should
2011 Jun 12
2
R graphs differ from exported one
Hello everybody! This is my first mail so I'll write a couple of lines
of self-introduction.
My name is Massimiliano, I'm from Italy and I'm studying Mathematical
Engineering.
I started using R in my Statistics course and have to use it to make a
project which I'll discuss at the end of the course.
The problem I'd like to ask you about follows.
Suppose I have imported a
2003 Oct 31
2
Therotical basis of Kriging
hello
I want to know about therotical basis of Kriging in elemantary level.
I will appreciate if anyone sends me address,link,e-documents, etc..
kind regards
--
Ahmet Temiz
General Directory of Disaster Affairs
Ankara TURKEY
______________________________________
Inflex - installed on mailserver for domain @deprem.gov.tr
Queries to: postmaster at deprem.gov.tr
2004 Aug 06
3
Bug in qnorm or pnorm?
I found the following strange behavior using qnorm() and pnorm():
> x<-8.21;x-qnorm(pnorm(x))
[1] 0.0004638484
> x<-8.22;x-qnorm(pnorm(x))
[1] 0.01046385
> x<-8.23;x-qnorm(pnorm(x))
[1] 0.02046385
> x<-8.24;x-qnorm(pnorm(x))
[1] 0.03046385
> x<-8.25;x-qnorm(pnorm(x))
[1] 0.04046385
> x<-8.26;x-qnorm(pnorm(x))
[1] 0.05046385
> x<-8.27;x-qnorm(pnorm(x))
2011 Mar 29
2
normal distribution and floating point traps (?): unexpected behavior
dear all,
here's a couple of questions that puzzled me in these last hours:
##### issue 1 qnorm(1-10e-100)!=qnorm(10e-100)
qnorm(1-1e-10) == -qnorm(1e-10)
# turns on to be FALSE. Ok I'm not a computer scientist but,
# but I had a look at the R inferno so I write:
all.equal(qnorm(1-1e-10) , -qnorm(1e-10))
# which turns TRUE, as one would expect, but
all.equal(qnorm(1-1e-100) ,
2012 Jun 18
3
(1-1e-100)==1 true?
Hi,
This problems has bothered me for the lase couple of hours.
> 1e-100==0
[1] FALSE
> (1-1e-100)==1
[1] TRUE
How can I tell R that 1-1e-100 does not equal to 1, actually, I found out
that
> (1-1e-16)==1
[1] FALSE
> (1-1e-17)==1
[1] TRUE
The reason I care about this is that I was try to use qnorm() in my code,
for example,
> qnorm(1e-100)
[1] -21.27345
and if I want to
2005 Mar 09
1
Trouble with mixreg
Dear All
I am trying to estimate a mixture of regression and get the
following error using the mixreg package:
Error in y - yhat : non-conformable arrays
The instruction I used were:
x <- as.matrix(LRHUN)
y <- as.matrix(LRINTER)
TS <- list(list(beta=c(3.0,1.0),sigsq=1,lambda=0.4),
list(beta=c(0.0,1.0),sigsq=1,lambda=0.6))
prova <- mixreg(x,y, ncomp=2, theta.start=TS)
2001 Jul 02
2
Shapiro-Wilk test
Hi,
does the shapiro wilk test in R-1.3.0 work correctly? Maybe it does, but can
anybody tell me why the following sample doesn't give "W = 1" and
"p-value = 1":
R> x<-1:9/10;x
[1] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
R> shapiro.test(qnorm(x))
Shapiro-Wilk normality test
data: qnorm(x)
W = 0.9925, p-value = 0.9986
I can't imagine a sample being
2017 Apr 16
1
Getting high precision values from qnorm in the tail
Hello All
I am looking for high precision values for the normal distribution in the
tail,(1e-10 and 1 - 1e-10) as the R package that I am using sets any number
which is out of this range to these values and then calls the qnorm and qt
function.
What I have noticed is that the qnorm implementation in R is not symmetric
when looking at the tails. This is quite surprising to me, as it is well
known
2004 Mar 05
6
qnorm(2) ends with segmentation fault (PR#6648)
Full_Name: Xiong Guanglei
Version: 1.8.1
OS: Linux
Submission from: (NULL) (202.38.103.50)
qnorm(x)
when x>1.0
2011 Aug 23
2
qnorm?
Hi everyone,
I have the following problem. I have some small p-values but when I use
qnorm(1-4e-30)
I get an error.
Is there anyway to get around this?
--
Thanks,
Jim.
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2013 May 20
4
Código del algoritmo de qnorm
Cordial saludo para cada uno.
De manera amable les pido ayuda para acceder al código R usado para el
algoritmo de la función qnorm.
Gracias por su ayuda.
César Escalante C.
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2009 Feb 05
2
How to implement HA and Live Migration with a SAN?
Hello,
I''ve configured two xen hosts (dom0) sharing a LUN on a SAN.
My firs obiective is to run different domU on the two hosts, and
implement live migration between them.
Subsequently, I''d like to implement HA, so if a xen host goes down,
domUs will be restarted on the other one.
What''s the better way to obtain this? I think I need a cluster file
system to