Hello everybody,

I am studying the impact of infrastructure on horticultural trade using a gravity equation at a product level. I will be using country-product and product-year fixed effects. The new "ppmlhdfe" command seems to be the best to use. However, it is taking a very long time to calculate. My dataset is about 2 million observations. Does this has something to do with the observations dropped due to be singletons or separated by fixed effects? Around 10443 observations are dropped due to this. (I have a lot of zero trade observations in this dataset)

Has someone experiences this? Any solutions?

Thank you.