I am new to R and forecasting .I have data for a certain product. It contains value sales and its promotions. The data is weekly and there are about 104 data points.
I converted the sales into a ts object and created seasonaldummy's to capture seasonality.
actual_val = ts(sku1$Sal , frequency = 52)
dummy_val = seasonaldummy(actual_val)
The dummy's were later combined with the promo variables to create external regressors xreg_val for the model. Those promotions which were not held for this sku were removed before combining the two.
model_value <- try(auto.arima(actual_val , xreg = xreg_val ) , silent = TRUE)
I have received the following error
Error in optim(init[mask], armaCSS, method = optim.method, hessian = FALSE,
non-finite value supplied by optim
I could not understand where exactly I have gone wrong in this.
Attaching a sample of the data. Kindly help me with this
https://drive.google.com/file/d/0B6sOv1da0JMeb01XYW92UzRSZ0U/view?usp=sharing
Best Answer
The following works in the sense that it returns a valid model:
Perhaps your problem is that you haven't defined
xreg_val
.However, it isn't a sensible model as you use 51 degrees of freedom for seasonality but have only two years of daily data. I suggest you use Fourier terms instead: