Yoink: An interaction‐based partitioning API

Herein, we describe the implementation details of our interaction‐based partitioning API (application programming interface) called Yoink for QM/MM modeling and fragment‐based quantum chemistry studies. Interactions are detected by computing density descriptors such as reduced density gradient, density overlap regions indicator, and single exponential decay detector. Only molecules having an interaction with a user‐definable QM core are added to the QM region of a hybrid QM/MM calculation. Moreover, a set of molecule pairs having density‐based interactions within a molecular system can be computed in Yoink, and an interaction graph can then be constructed. Standard graph clustering methods can then be applied to construct fragments for further quantum chemical calculations. The Yoink API is licensed under Apache 2.0 and can be accessed via yoink.wallerlab.org. © 2018 Wiley Periodicals, Inc. Yoink uses density‐based descriptors to detect interactions to partition a molecular system. Robust partitioning criteria are required for region assignment in multi‐scale simulations and in graph‐based clustering for divide and conquer type approaches.