Displaying 20 results from an estimated 400 matches similar to: "R question"
2023 Jan 05
1
R 'arima' discrepancies
Rob J Hyndman gives great explanation here
(https://robjhyndman.com/hyndsight/estimation/) for reasons why results
from R's arima may differ from other softwares.
@iacobus, to cite one, 'Major discrepancies between R and Stata for
ARIMA'
(https://stackoverflow.com/questions/22443395/major-discrepancies-between-r-and-stata-for-arima),
assign the, sometimes, big diferences from R
2018 Mar 15
1
Adjusting OHCL data via quantmod
Hello,
I'm trying to do two things:
-1. Ensure that I understand how quantmod adjust's OHLC data
-2. Determine how I ought to adjust my data.
My overarching-goal is to adjust my OHLC data appropriately to minimize the
difference between my backtest returns, and the returns I would get if I
was trading for real (which I'll be doing shortly).
Background:
-1. I'm using Alpha
2018 May 15
3
Forecasting tutorial "Basic Forecasting"
Hi. I am trying to follow this forecasting tutorial at: https://www.r-bloggers.com/basic-forecasting/
Using my own data, I cannot get past the first step, lots of laughs.
dat3 <- structure(c(5973156.76, 5159011.20, 6695766.64, 6365359.00, 6495218.53, 7226302.39, 6835272.70, 7383501.57, 6962748.19, 7623278.72, 7274994.33
,7919421.80, 7360740.81, 7436693.35,
2012 Apr 17
2
Manually reconstructing arima model from coefficients
Colleagues
I am a new to R but already love it.
I have the following problem:
I fitted arima model to my time series like this (please ignore modeling
parameters as they are not important now):
x = scan("C:/data.txt")
x = ts(x, start=1, frequency=1)
x.fit<-arima(x, order = c(1,0,0), seasonal = list(order=c(0,0,1)))
Now I want to use this model for forecasting and backtesting (!).
2012 Dec 04
4
partial analisys of a time series
Dear list members
I want to analyze separately the months of a time series. In other words, I
want to plot and fit models for each month separately.
Taking the example of
http://a-little-book-of-r-for-time-series.readthedocs.org/en/latest/src/timeseries.html
births <- scan("http://robjhyndman.com/tsdldata/data/nybirths.dat")
birthstimeseries <- ts(births, frequency=12,
2018 May 15
0
Forecasting tutorial "Basic Forecasting"
Instead of
Tsp = c(2016, 2018, 12)
try
Tsp = c(2016, 2018.25, 12)
Hence, you can specify the object as
structure(c(5973156.76, 5159011.2, 6695766.64, 6365359, 6495218.53,
7226302.39, 6835272.7, 7383501.57, 6962748.19, 7623278.72, 7274994.33,
7919421.8, 7360740.81, 7436693.35, 8545765.55, 7337269.76, 8180585.44,
8376635.05, 7758261.24, 10374641.22, 8000314.11, 9114958.9, 9805149.15,
2011 Jun 02
1
Line histogram for a matrix
Hi guys!
I'm new to R, but I was wondering if one could plot many histograms into a
single graph each having a different color. To make things clear:
Suppose you have a matrix of 100 rows and 10 columns. I'm interested in
plotting the histogram for each row, but it should not appear as bars but
rather as lines connecting the points of the frequencies. Now, I want to do
this for the 100
2016 Feb 08
3
tamaño de rolling window (series temporales)
Hola!!
Estoy intentando evaluar mi modelo de series temporales (uso auto.arima).
Para ello he implemetado el método "rolling window" que se basa en ir
añadiendo progresivamente datos al conjunto de train para testar el
modelo. Por ejemplo:
- Train: 1 año, test: día 1 (24 observaciones, una por hora) --> evalúo
ese día (RMSE por ejemplo)
- Train: 1 año + 1 día, test: día 2 -->
2010 Mar 19
1
Arima forecasting
Hello everyone,
I'm doing some benchmark comparing Arima [1] and SVR on time series data.
I'm using an out-of-sample one-step-ahead prediction from Arima using
the "fitted" method [2].
Do someone know how to have a two-steps-ahead forecast timeseries from Arima?
Thanks,
Matteo Bertini
[1] http://robjhyndman.com/software/forecast
[2] AirPassengers example on page 5
2011 Mar 28
1
portfolioBacktest in fPortfolio
Hello. I am trying to use the portfolio backtesting function in fPortfolio
package, but I don't now why in my version of fPortfolio I don't have either
the portfolioBactest nor the portfolioBacktesting functions. Does anybody
knows what might be going on?
thank you
Felipe Parra
[[alternative HTML version deleted]]
2010 Jul 10
1
quantstrat and blotter unavailable
These packages were not available. Are these the only places to go for
backtesting technical trading systems other than ttrTests pls?
> install.packages("quantstrat", repos="http://R-Forge.R-project.org")
Warning in install.packages("quantstrat", repos = "
http://R-Forge.R-project.org") :
argument 'lib' is missing: using
1998 Jul 01
4
Serious Linux 2.0.34 security problem (fwd)
---------- Forwarded message ----------
Date: Tue, 30 Jun 1998 15:10:47 +0800
From: David Luyer <luyer@UCS.UWA.EDU.AU>
To: BUGTRAQ@NETSPACE.ORG
Subject: Serious Linux 2.0.34 security problem
I just saw this mentioned on linux-kernel and confirmed it;
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(int
2009 Apr 05
1
Time series forecasting
Dear all:
I'm a newbie and an amateur seeking help with forecasting the next in a non-stationary time series, with constraints of 1 (low) and 27 (high) applicable to all.
What I need help with is the solution concept. The series has 439 observations as of last week. I'd like to analyze obs 1 - 30 (which are historical and therefore invariate), to solve for 31.
The history:
Obs 1
2008 Apr 08
1
Weibull maximum likelihood estimates for censored data
Hello!
I have a matrix with data and a column indicating whether it is censored
or not. Is there a way to apply weibull and exponential maximum
likelihood estimation directly on the censored data, like in the paper:
Backtesting Value-at-Risk: A Duration-Based Approach, P Chrisoffersen
and D Pelletier (October 2003) page 8?
The problem is that if I type out the code as below the likelihood
2017 Feb 15
2
stats::median
The generic stats::median method is defined as
median <- function (x, na.rm = FALSE) {UseMethod("median")}
I suggest that this should become
median <- function (x, na.rm = FALSE, ...) {UseMethod("median")}
This would allow additional S3 methods to be developed with additional
arguments.
Currently I have to over-ride this generic definition in the
demography
2009 Jul 21
1
Forecasting - Croston Method Error
Hi,
I tried to use the Croston function from the forecasting package
1.24<http://robjhyndman.com/software/forecasting> with
the code below, but I get in return this message "*Error in
decompose(ts(x[1L:wind], start = start(x), frequency = f), seasonal) : time
series has no or less than 2 periods*".
histValues
2009 May 01
1
Last month on the Revolutions blog
I write about R every weekday at?http://blog.revolution-computing.com
. In case you missed them, here are some articles from the month of
April of particular interest to r-help subscribers. Thanks to everyone
who has been following the blog and sending me messages and/or leaving
comments -- it always brightens my day to hear from readers!
http://tinyurl.com/cy7x9a?(from April 1) announced the new
2017 Mar 01
1
stats::median
>>>>> Martin Maechler <maechler at stat.math.ethz.ch>
>>>>> on Mon, 27 Feb 2017 10:42:19 +0100 writes:
>>>>> Rob J Hyndman <Rob.Hyndman at monash.edu>
>>>>> on Wed, 15 Feb 2017 21:48:56 +1100 writes:
>> The generic stats::median method is defined as median <-
>> function (x, na.rm = FALSE)
2011 Jun 16
5
Porting "unmaintained" packages to post R 2.10.0 era
Hi all,
I am trying to re-compile some "unmaintained" (it seems) packages, namely rSoNIA
and dynamicnetwork from:
http://csde.washington.edu/~skyebend/rsonia/rsoniaDemo/
These packages predates R 2.10.0 so they need to be recompile.
After split the single big file in /man in each packages into a file for each
function + some minor fix, I successfully manage to recompile and load
2009 Oct 23
3
How to make R packages?
I found the following document on making R packages. But it is old.
I'm wondering if there is more current ones and hopefully more
complete ones.
http://biosun1.harvard.edu/courses/individual/bio271/lectures/L6/Rpkg.pdf