I would like to fit an LSTM model using MXNET in R for the purpose of predicting a continuous response (i.e., regression) given several continuous predictors. However, the mx.lstm() function seems to be geared toward NLP as it requires arguments which don't seem applicable to a regression problem (such as those related to embedding).
Is MXNET capable of this sort of modeling and, if not, what is an example of an appropriate tool (preferably in R)? Are there any tutorials relevant to the problem I've described?
LSTM is used for working with temporal data: text, speech, time series. If you want to predict a continuous response, then I assume you want to do something similar to time series analysis.
If my assumption is correct, then, please, take a look here. It gives quite a good example on how to use MxNet with R for time series on CPU. The GPU version is also available here.
Related
I have used Tidymodel to build a logistic regression model.
While I can extract the performance metrics, I would like to plot the agreement between predictions and observations (calibration plot)
But, have yet to find a method to do this - has anyone got experience with this?
tidymodels does not have a calibration plot function yet (I'm literally working on that now). I would suggest using the one in caret. I don't expect our work to be ready for a while.
I am working with the R programming language. In particular, I am using "Markov Switching Models" for the purpose modelling more complicated dataset with varying degrees of volatility. For this problem, I am using the "MSwM" package in R:
https://cran.r-project.org/web/packages/MSwM/MSwM.pdf
https://cran.r-project.org/web/packages/MSwM/vignettes/examples.pdf
I am following the first example from the "vignettes":
#load library
library(MSwM)
#load data
data(example)
#plot data
plot(ts(example))
#fit basic model
mod=lm(y~x,example)
#fit markov switching model:
mod.mswm=msmFit(mod,k=2,p=1,sw=c(TRUE,TRUE,TRUE,TRUE),control=list(parallel=FALSE))
The above code successfully creates the model - 2 "Regimes" have been identified:
Question: I checked the documentation of this package, and there does not seem to be any functions that allow you to predict future values of this time series. I did some research and it seems like the "Markov Switching Model" should allow you to predict future values of a time series, e.g. : https://stats.stackexchange.com/questions/90448/how-to-forecast-a-markov-switching-model
OR:
However, there does not seem to be a straightforward way to do this in R. Can someone please suggest how to resolve this problem?
Thanks
I am working on quantile forecasting with time-series data. The model I am using is ARIMA(1,1,2)-ARCH(2) and I am trying to get quantile regression estimates of my data.
So far, I have found "quantreg" package to perform quantile regression, but I have no idea how to put ARIMA-ARCH models as the model formula in function rq.
rq function seems to work for regressions with dependent and independent variables but not for time-series.
Is there some other package that I can put time-series models and do quantile regression in R? Any advice is welcome. Thanks.
I just put an answer on the Data Science forum.
It basically says that most of the ready made packages are using so called exact test based on assumption on the distribution (independent identical normal-Gauss distribution, or wider).
You also have a family of resampling methods in which you simulate a sample with a similar distribution of your observed sample, perform your ARIMA(1,1,2)-ARCH(2) and repeat the process a great number of times. Then you analyze this great number of forecast and measure (as opposed to compute) your confidence intervals.
The resampling methods differs in the way to generate the simulated samples. The most used are:
The Jackknife: in which you "forget" one point, that is you simulate a n samples of size n-1 (if n is the size of the observed sample).
The Bootstrap: in which you simulate a sample by taking n values of the original sample with replacements: some will be taken once, some twice or more, some never,...
It is a (not easy) theorem that the expectation of the confidence intervals, as most of the usual statistical estimators, are the same on the simulated sample than on the original sample. With the difference that you can measure them with a great number of simulations.
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I can try to address your question, although this is hard since you don't provide any code/data. Also, I guess by "put ARIMA-ARCH models" you actually mean that you want to make an integrated series stationary using an ARIMA(1,1,2) plus an ARCH(2) filters.
For an overview of the R time-series capabilities you can refer to the CRAN task list.
You can easily apply these filters in R with an appropriate function.
For instance, you could use the Arima() function from the forecast package, then compute the residuals with residuals() from the stats package. Next, you can use this filtered series as input for the garch() function from the tseries package. Other possibilities are of course possible. Finally, you can apply quantile regression on this filtered series. For instance, you can check out the dynrq() function from the quantreg package, which allows time-series objects in the data argument.
I am new to using R as I usually use Stata. I want to estimate a state space model on some time series data with time varying coefficients. From what I have gathered this is not possible to do in Stata.
I have downloaded the dlm package in R and I am trying to run the dlmModReg command to regress my dependent variable on a single explanatory variable. I would like to allow the intercept and beta coefficient to vary over time.
If anyone could show me an example of the code I want to run I think that would be enough for me to work out how to do this. The examples I have found online are vague or use terminology that I am not familiar with as a new R user. Any help or comments are greatly appreciated.
I've been attempting to perform an ANOVA in R recently on the attached data frame.
My question revolves around the setting of contrasts.
My design is a 3x5 within-subjects design.
There are 3 visual conditions under 'Circle1' and 5 audio under 'Beep1'.
Does anyone have any idea how I should set the contrasts? This is something I'm unfamiliar with as I'm making the transition from point and click stats in SPSS to coded in R.
Thanks for your time
Data file:
Reiterating my answer from another stackoverflow question that was flagged as similar, since you didn't provide any code, you might start by having a look at the contrast package in R. As they note in the document:
"The purpose of the contrast package is to provide a standardized interface for testing linear combinations of parameters from common regression models. The syntax mimics the contrast. Design function from the Design library. The contrast class has been extended in this package to linear models produced using the functions lm, glm, gls, lme and geese."
There is also a nice little tutorial here by Dr. William King who talks about factorial between subjects ANOVA and also includes an abundance of R code. This is wider scoped than you question but would be a great place to start (just to get context).
Finally, here is another resource that you can refer to which talks about setting up orthogonal contrasts in R.