GLM Asymmetric Matrix

[geo]

Dear all,

My apologies for the basic question.

I would like to set up a GLM model in BEAST X to evaluate the effect of several predictors on viral dispersal. One of the predictors I am interested in is animal trade among countries.

However, trade flows are clearly asymmetric between country pairs. For example, England may import 1,000 units of a given product from Germany, whereas Germany may import only 10 units of the same product from England.

Is the GLM framework in BEAST X able to accommodate such asymmetric predictors? If so, how should the predictor matrix be organized in terms of rows and columns? Should the matrix reflect directional flows (i.e., origin → destination), or is a different structure required?

Thank you very much for any advice or suggestions you can provide.

Best regards,
Geo