Provide a mathematical model for selecting suppliers in the supply chain based on profit efficiency calculations

One of the most important issues in managers' decisions is supplier selection and supply chain evaluation. Therefore, several studies have been conducted on supplier selection and evaluation by data envelopment analysis. But studies so far have focused on selecting suppliers and evaluating them. And there is no way to determine the number of suppliers in a supply chain. Therefore, in this article, we first express the concept of profit efficiency for supply chains and using the proposed model in this paper, the number and type of suppliers in a supply chain are determined simultaneously. Finally, 10 "supply chains" in the food industry were examined and the profit efficiency of each of them was calculated using the proposed model in this article, and then the number and type of suppliers in each chain were determined.