similar to: Please Help!

Displaying 20 results from an estimated 30000 matches similar to: "Please Help!"

2011 Sep 14
3
Loops
Dear forum, I would like to forecast e.g. with the arima-model. To figure out which model works best I am going to predict with this models. my first code: for(ar.ord in 1:3){ for(ma.ord in 1:3){ print(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)), n.ahead=8)$pred) } } this one works. but I want to "save" my results in a matrix or a data.frame. my second code:
2007 Dec 24
2
ARIMA problem
Hi, This is regarding the ARIMA model. I am having time series data of stock of 2000 values. Using the ARIMA model in R, I want the forcasted values for next 36 time points. However when I run this model in R, I am getting same value for all 36 time points. I have tried to fit the data with ARIMA model by changing the parameters p,d,q after looking at the errors and other criteria for
2010 Aug 19
1
How to include trend (drift term) in arima.sim
I have been trying to simulate from a time series with trend but I don't see how to include the trend in the arima.sim() call. The following code illustrates the problem: # Begin demonstration program x <- c(0.168766559, 0.186874000, 0.156710548, 0.151809531, 0.144638812, 0.142106888, 0.140961714, 0.134054659, 0.138722419, 0.134037018, 0.122829846, 0.120188714,
2011 Sep 20
2
ARIMA - Skipping intermediate lags
Hello, I am a new R user. I am trying to use the arima command, but I have a question on intermediate lags. I want to run in R the equivalent Stata command of ARIMA d.yyy, AR(5) MA(5 7). This would tell the program I am interested in AR lag 5, MA lag 5, and MA lag 7, all while skipping the intermediate lags of AR 1-4, and MA 1-4, 6. Is there any way to do this in R? Thank you. -- View this
2007 Aug 31
3
Choosing the optimum lag order of ARIMA model
Dear all R users, I am really struggling to determine the most appropriate lag order of ARIMA model. My understanding is that, as for MA [q] model the auto correlation coeff vanishes after q lag, it says the MA order of a ARIMA model, and for a AR[p] model partial autocorrelation vanishes after p lags it helps to determine the AR lag. And most appropriate model choosed by this argument gives
2003 Jul 16
1
arima.sim problems (PR#3495)
Full_Name: Gang Liang Version: 1.7.1 OS: Debian/Woody Submission from: (NULL) (192.6.19.190) > print(arima.sim(list(ar=.3,order=c(1,1,1)), 30)) [1] 0.00000000 0.10734243 0.02907301 -1.23441659 -0.98819317 -2.82731975 [7] -2.69052512 -4.22884756 -5.02820635 -5.41514613 -6.20486350 -7.01040649 [13] -6.78121289 -5.41111810 -4.96338053 -5.42395408 -6.22741444 -5.75228153 [19] -6.07346580
2011 Aug 30
2
ARMA show different result between eview and R
When I do ARMA(2,2) using one lag of LCPIH data This is eview result > > *Dependent Variable: DLCPIH > **Method: Least Squares > **Date: 08/12/11 Time: 12:44 > **Sample (adjusted): 1970Q2 2010Q2 > **Included observations: 161 after adjustments > **Convergence achieved after 14 iterations > **MA Backcast: 1969Q4 1970Q1 > ** > **Variable Coefficient Std.
2003 Aug 14
1
filter ARMA process
Hi given an ARMA process and the AR and MA coefficients I need the residuals. arima() calculates the residuals together with the best AR and MA coefficients, but I need the coefficients to take known values. In S-PLUS there is a function arima.filt(). Is there something similar in R? Thanks for any help, Matthias Budinger
2009 Jun 05
1
Bug in print.Arima and patch
Dear List, A posting to R-Help exposed this problem with the print method for objects of class Arima: > set.seed(1) > x <- arima.sim(n = 100, list(ar = 0.8897, ma = -0.2279)) > mod <- arima(x, order = c(1,0,1)) > coefs <- coef(mod) > mod2 <- arima(x, order = c(1,0,1), fixed = coefs) > mod2 Call: arima(x = x, order = c(1, 0, 1), fixed = coefs) Coefficients: Error
2007 Mar 05
1
Heteroskedastic Time Series
Hi R-helpers, I'm new to time series modelling, but my requirement seems to fall just outside the capabilities of the arima function in R. I'd like to fit an ARMA model where the variance of the disturbances is a function of some exogenous variable. So something like: Y_t = a_0 + a_1 * Y_(t-1) +...+ a_p * Y_(t-p) + b_1 * e_(t-1) +...+ b_q * e_(t-q) + e_t, where e_t ~ N(0, sigma^2_t),
2009 Jun 22
2
question about using _apply and/or aggregate functions
Hi R-list, I'll apologize in advance for (1) the wordiness of my note (not sure how to avoid it) and (2) any deficiencies on my part that lead to my difficulties. I have an application with several stages that is meant to simulate and explore different scenarios with respect to product sales (in units sold per month). My session info is at the bottom of this note. The steps include (1) an
2008 Mar 21
1
tseries(arma) vs. stats(arima)
Hello, The "arma" function in the "tseries" package allows estimation of models with specific "ar" and "ma" lags with its "lag" argument. For example: y[t] = a[0] + a[1]y[t-3] +b[1]e[t-2] + e[t] can be estimated with the following specification : arma(y, lag=list(ar=3,ma=2)). Is this possible with the "arima" function in the
2007 Nov 08
1
Help me please...Large execution time in auto.arima() function
Hello, I using the fuction auto.arima() from package forecast to predict the values of p,d,q and P,D,Q. My problem is the execution time of this function, for example, a time series with 2323 values with seasonality to the week take over 8 hours to execute all the possibilities. I using a computer with Windows XP, a processor Intel Core2 Duo T7300 and 2Gb of RAM.
2008 Mar 24
2
Commands failing silently?
Hello all: I have a couple CentOS 4 servers (all up-to-date) that are having strange command failures. I first noticed this with a perl script that uses lots of system calls. Basically, sometimes a command just won't run: thoth(52) /tmp> ls thoth(53) /tmp> ls thoth(54) /tmp> ls thoth(55) /tmp> ls learner lost+found/ thoth(56) /tmp> ls learner lost+found/ thoth(57)
2013 Feb 14
1
hyper-parameters
I'm searching a method to estimate the hyper-parameters in arima models. I'm reading about r-inla package, but in the examples section only talk about the AR part of the arima, but i need help about the MA part too. I'm beginner in Bayesian methods, I'm reading the documentation about dlm package and kalman filters, but the computacional cost of inla i think is better, but only
2020 Jan 04
2
A modern object-oriented machine learning framework in R
Estimadísimo Carlos: Muchísimas gracias por responderme y hacerlo tan rápido. Contemplé esa posibilidad, es decir, que el hiperparámetro estuviera suponiendo un problema, y probé de esta forma: > learner <- lrn("classif.ranger", num.trees = 5, mtry = NULL) Error: Element with key 'classif.ranger' not found in DictionaryLearner!
2010 Jan 30
1
MA parameter in R vs. Minitab
Dear R People: I ran an ARIMA(1,0,1) on a particular series in R and got a negative MA(1) estimate. Then I ran an ARIMA(1,0,1) on the same series in Minitab and got a positive MA(1) estimate. The values are about -0.69 and 0.70. Does R show the opposite value, please? Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston -
2007 Feb 26
1
Partial whitening of time series?
I have a time series with a one year lag, ar=0.5. The series has some interesting events that disappear when the series is whitened (i.e., fitting an AR process and looking at the residuals). I'd like to remove the autocorrelation in stages to see the effect on the time series. Is there a way to specify the autocorrelation term while fitting an AR process? For instance, given the following:
2005 Oct 13
1
arima: warning when fixing MA parameters.
I am puzzled by the warning message in the output below. It appears whether or not I fit the seasonal term (but the precise point of doing this was to fit what is effectively a second seasonal term). Is there some deep reason why AR parameters ("Warning message: some AR parameters were fixed: ...") should somehow intrude into the fitting of a model that has only MA terms? >
2012 Mar 20
1
MA process in panels
Dear R users, I have an unbalanced panel with an average of I=100 individuals and a total of T=1370 time intervals, i.e. T>>I. So far, I have been using the plm package. I wish to estimate a FE model like: res<-plm(x~c+v, data=pdata_frame, effect="twoways", model="within", na.action=na.omit) ?where c varies over i and t, and v represents an exogenous impact on x