Displaying 20 results from an estimated 26 matches for "phi2".
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2010 Apr 14
0
ur.df ADF Unit Root Test: what is the meaning of phi1 and phi2 test statistic?
Hello,
I am using the ur.df function from the {arca} package to run the augmented
Dickey-Fuller unit root test on several time series. However; I do not
understand the econometric interpretation of the the "phi1" and "phi2"
test-statisitc which are output if you choose a "trend" or "drift" model. I
looked at the source code for the function but I do not quite understand the
code (which I have included below). Any help would be much appreciate.
Thanks,
Max
if (type == "drift") {...
2011 Feb 06
1
anova() interpretation and error message
...s.A
P Biomass
1 334.5567 0.2870000
2 737.5400 0.5713333
3 894.5300 0.6393333
4 782.3800 0.5836667
5 857.5900 0.6003333
6 829.2700 0.5883333
I have fit the data using logistic, Michaelis?Menten, and linear model,
they all give significance.
> fm1 <- nls(Biomass~SSlogis(P, phi1, phi2, phi3), data=Ca.P.Biomass.A)
> fm2 <- nls(Biomass~SSmicmen(P, phi1, phi2), data=Ca.P.Biomass.A)
> fm3 <- lm(Biomass~P, data = Ca.P.Biomass.A)
I hope to compare the difference among the three models, and I using
anova(). As for the example here, the three models seem not have
signif...
2008 Apr 04
1
Problems with Unit Root testing using ur.df function
...teststat <- as.matrix(t(c(tau, phi1)))
colnames(teststat) <- c('tau2', 'phi1')
}
if (type == "trend") {
result <- lm(z.diff ~ z.lag.1 + 1 + tt + z.diff.lag)
tau <- coef(summary(result))[2, 3]
phi2.reg <- lm(z.diff ~ -1 + z.diff.lag)
phi3.reg <- lm(z.diff ~ z.diff.lag)
phi2 <- anova(phi2.reg, result)$F[2]
phi3 <- anova(phi3.reg, result)$F[2]
teststat <- as.matrix(t(c(tau, phi2, phi3)))
colnames(teststat) <- c('t...
2003 Aug 14
1
gnls - Step halving....
...the parameters those obtained from the nls
fit. Is a problem of the initial estimates of the
parameters that I get the error or could be something
else?
The code for the nls fit was:
options(contrasts=c("contr.helmert","contr.poly"))
VA1.lis<-nlsList(DRAM~SSlogis(MED,phi1,phi2,phi3)|TRAT,
data=VA1,na.action=na.omit)
The code for the gnls fit was (using a 'difference
parameterization' like SAS):
options(contrasts=c("contr.SAS","contr.poly"))
VA1.gnls<-gnls(DRAM~SSlogis(MED,phi1,phi2,phi3),
data=VA1,params=list(phi1~TRAT,phi2~TRAT,phi3~TRA...
2006 Nov 06
1
question about function "gls" in library "nlme"
Hi:
The gls function I used in my code is the following
fm<-gls(y~x,correlation=corARMA(p=2) )
My question is how to extact the AR(2) parameters from "fm".
The object "fm" is the following. How can I extract the correlation parameters
Phi1 and Phi2 from "fm"? These two parametrs is not in the "coef" componenet of "fm".
Thanks a lot!
liu
--------------------------------------------------------------------------------------------------------------
> fm
Generalized least squares fit by REML
Model: y ~...
2007 Aug 23
1
degrees of freedom question
R2.3, WinXP
Dear all,
I am using the following functions:
f1 = Phi1+(Phi2-Phi1)/(1+exp((log(Phi3)-log(x))/exp(log(Phi4)))
f2 = Phi1+(Phi2-Phi1)/(1+exp((log(Phi3)-log(r)-log(x))/exp(log(Phi4)))
subject to the residual weighting
Var(e[i]) = sigma^2 * abs( E(y) )^(2*Delta)
Here is my question, in steps:
1. Function f1 is separately fitted to two different datasets...
2001 Aug 30
1
MCMC coding problem
...ep(data,t1): invalid number of copies in "rep".
This happens no matter what values that I give the parameters when I call
the function.
Any suggestions on clearing this up would be appreciated! The function is
printed below.
Many Thanks,
Monnie McGee
mcmcmd <- function(d, w, mean, phi2, varwt, ntimes)
{
# A function to run a multi dimensional MCMC for a bivariate
# normal distribution
# d = dimension of problem
# w = weight assigned to larger of two modes in target distribution
# mu = mean of second mode
# phi2 = multiplier of variance factor 2.38
# varwt = weight (0 < varw...
2007 Mar 10
1
installation pb on debian etch
...NGLISH :ekiga cannot subscribe
I don't know where is the solution.
Can anybody help me ?
thanks.
==========
Here are the significant lines of my sip.conf
,----
| [general]
| context=default
| bindport=5060
| bindaddr=0.0.0.0
| srvlookup=yes
| disallow=all
|
| register => phi2:6641ekiganet@ekiga.net/1234
|
| [authentication]
|
| [ekiganet-out]
| type=peer
| secret=6641ekiganet
| username=phi2
| host=ekiga.net
| call-limit=5
| context=from-ekiganet
|
| [ekiga1]
| type=friend
| host=dynamic
| username=ekiga1
| secret=6641ekiga1
| disallow=all...
2017 Oct 18
4
Error messages using nonlinear regression function (nls)
...wheat = germination[germination$species == "wheat",] ### subset by wheat
scatterplot(Prop ~ end|temp,data=wheat,box=FALSE,reg=FALSE) ### view the data
wheat$temp = as.factor(wheat$temp) ### convert to factor
### First, try to use nlsList
wheat.list <- nlsList(Prop ~ SSlogis(end,phi1,phi2,phi3)| temp,pool=FALSE,data=wheat) ###
### next, try to use lm to estimate starting parameters.
wheat.list = list()
for (i in 1:length(levels(wheat$temp))){
tmpDat = wheat[wheat$temp == levels(wheat$temp)[i],]
tmp.lm <- lm(Prop ~ end,data = tmpDat)
tmp.nls <- nls(Prop ~ theta1 / (1 +...
2008 Mar 10
1
state space model for poisson distribution
...sure about the codes to combine these two on R. If anybody has any R example (code), please post it.
My original model: log(Y(t))~constant+b1*Y(t-1)+b2*Y(t-2)+b3*(variable1)+b4*(variable2)+e
I would like to construct a model:
log(Y(t))~constant+b1*(variable1)+b2*(variable2)+X(t)
X(t)~phi1*Xt-1+phi2*Xt-2+error
where X(t) is the autoregressive lag effect of response.
A.K.
---------------------------------
[[alternative HTML version deleted]]
2011 Dec 05
1
extract cov matrix in summary.rq and use as a matrix.
Dear all,
I need to extract the covariance matrix of my quantile regression estimation to use in a test. My regression is:
qf2_1 <- summary(rq(wb2 ~ apv2 + vol2, tau = phi2[1]), cov = TRUE)
I can extract the covaraince matrix by using: qf2_1 [3]. However, if I try to use it in the test, it does not work. I only need to transform qf2_1[3] in a matrix 3x3. I have already tried: matrix(qf2_1[3], nrow=3, ncol=3) but it also does not work. By using the latter, I find:...
2005 Sep 06
1
R: optim
...roduced by the optim
function. can anybody help???
ie:
[[1]]$message
[1] "CONVERGENCE: REL_REDUCTION_OF_F <= FACTR*EPSMCH"
can anyone help?
###########################################################################
SK.FIT(XDATA=a,XDATAname="a",PHI1=1,v=5,vlo=2,vhi=300,phi2lo=.01)
[[1]]
[[1]]$par
[1] -0.01377906 0.83859445 0.34675230 300.00000000
[[1]]$value
[1] 90.59185
[[1]]$counts
function gradient
53 53
[[1]]$convergence
[1] 0
[[1]]$message
[1] "CONVERGENCE: REL_REDUCTION_OF_F <= FACTR*EPSMCH"
##################################...
2002 May 24
5
intersecting polygons and conversion from decimal degree to km
Dear all,
1. How can I compute the intersecting area between 2 polygons ?
2. I have polygons with coordinates in decimal degrees (i.e. 13 deg 30
min = 13.5 decimal degrees). I want to compute their area and get the
results in square meters or square kiometers. Can anyone give me a
conversion coefficient or a pointer where I can find this information
(sorry for this off topic question) ?
Thanks
2010 Nov 18
0
On efficiency, Vectorize and loops
...alization of an AR(1) process.
xi<-matrix(0,nrow=d,ncol=n)
for (i in 1:d){
theta<-(-1)^i * (.9 - .5*i/d)
xi[i,]<-arima.sim(model=list(ar=theta), n, rand.gen = rnorm)
}
rm(i, theta)
#Defining the deterministic base functions 'phi'
phi<-function(u,i){
sqrt(2)*cos(pi*i*u)
}
phi2<-function(i){force(i);
function(u){
sqrt(2)*cos(pi*outer(i,u))
}
}
phi3<-function(u,i){
sqrt(2)*cos(pi*outer(i,u))
}
# Building the random functional process 'X'
X<-lapply(1:n, function(t)local({force(t);
function(u){
X<-0
for (i in 1:d){
X<-X+xi[i,...
2018 Sep 05
4
Can I control HSA config generated by AMDGPU backend?
Finally I kind of modified llvm to generate assembly that can run on AMDGPU
pro drivers. One problem is the performance of the code generated by llvm
is about 10% slower than amdgpu's online compiler. Anything I can tune the
performance up the performance of llvm?\
Thanks!
On Tue, Sep 4, 2018 at 9:23 AM 董昌道 <dongchangdao at gmail.com> wrote:
> I am writing a miner of crypto
2003 Jun 03
1
tseries "adf.test"
I have a question regarding the adf.test command in the tseries library.
I have a vector of time series observations (2265 daily log prices for the
OEX to be exact). I also have this same data in first-differenced form. I
want to test both vectors individually for staionarity with an Augmented
Dickey-Fuller test. I noticed when I use the adf.test command from the
tseries library, the general
2008 Feb 08
0
User-specified correlation structure (e.g., 2-banded Toeplitz)
...1), Orthodont,
+ correlation = corARMA(value = c(0,-.3), form = ~
1 | Subject, p = 2, q = 0),
+ weights = varIdent(form = ~ 1 | age))
#-- Selected output follows-----
Correlation Structure: ARMA(2,0)
Formula: ~1 | Subject
Parameter estimate(s):
Phi1 Phi2
0.3269544 0.4897645
--------------------- End R-code & output --------------------------------
I cannot figure out how to restrict RHO1 = 0, while allowing
estimation of RHO2.
Maybe an answer lies in specifying a different ``position vector''
other than the default: corARMA(..., form...
2008 Feb 08
0
User specified correlation structure (e.g., 2-banded Toeplitz)
...11), Orthodont,
+ correlation = corARMA(value = c(0,-.3), form = ~
1 | Subject, p = 2, q = 0),
+ weights = varIdent(form = ~ 1 | age))
#-- Selected output follows-----
Correlation Structure: ARMA(2,0)
Formula: ~1 | Subject
Parameter estimate(s):
Phi1 Phi2
0.3269544 0.4897645
--------------------- End R-code & output --------------------------------
I cannot figure out how to restrict RHO1 = 0, while allowing
estimation of RHO2.
Maybe an answer lies in specifying a different ``position vector''
other than the default: corARMA(..., form...
2008 Feb 12
0
nlme & special case of corARMA?
...correlation = corARMA(value = c(0,-.3),
+ form = ~ 1 | Subject, p = 2, q = 0),
+ weights = varIdent(form = ~ 1 | age))
#-- Selected output follows-----
Correlation Structure: ARMA(2,0)
Formula: ~1 | Subject
Parameter estimate(s):
Phi1 Phi2
0.3269544 0.4897645
--------------------- End R-code & output --------------------------------
I cannot figure out how to restrict RHO1 = 0, while allowing
estimation of RHO2.
Maybe an answer lies in specifying a different ``position vector''
other than the default: corARMA(..., form...
2011 Jan 04
0
95% CI of the "Predicted values" from the GLS Model
...2712 422 7357
+2782 456 4669
Generalized least squares fit by maximum likelihood
Model: log(y) ~ log(x) + d1 + d3
Data: NULL
AIC BIC logLik
-166.2344 -147.8469 92.1172
Correlation Structure: ARMA(2,2)
Formula: ~1
Parameter estimate(s):
Phi1 Phi2 Theta1 Theta2
0.65960193 0.26221313 -0.02561896 -0.37995110
Coefficients:
Value Std.Error t-value p-value
(Intercept) -2.4304969 0.8078837 -3.008474 0.004
log(x) 1.0558775 0.0684389 15.428027 0.000
d1 0.2105713 0.0110250...