Dear Statalist forum,

I am currently tring to run a gravity equation using the PPMLHDFE command and saving the estimates for my fixed effects, as i have to use these in a further study. The regression i am running is the following:

ppmlhdfe trade, abs( i#k j#k i#j)


Where:

i= Exporter
j= Importer
k= sector (HS6 - 5200 different in the dataset).

I have bilateral trade for 99 countries and therefore i in total have : 50,440,698. I am using STATA I/C and running the regression on a computer with 32 GB ram and I7 processor.
The problem is that the regression never seems to begin the furthest i have gotten is this:

ppmlhdfe v, abs(i#k j#k i#j, savefe)
(dropped 1.84e+07 observations that are either singletons or separated by a fixed effect)

It never begins undertaking the iterations.

My question is am i simply demanding to much of my system ? Or is there something i am doing wrong in terms of the coding?.. I have look through several forums and cant seem to find an answer for this.


After having read some of PPMLHDFE: Fast Poisson Estimation withHigh-Dimensional Fixed Effects, i would expect on of the following to be able to answer this:

Sergio Correia Tom Zylkin Paulo Guimaraes


However advice from anyone, would be highly apperciated !