OpenSees Cloud
OpenSees AMI
Not Just a Modeling Term
Original Post - 13 Jun 2020 - Michael H. Scott
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“Master/slave” is common terminology to describe relationships in many technical fields, e.g., between tables in databases or between devices in control systems. The terminology also appears in finite element analysis where the response of one node controls the response of another node through constraints.
However, this terminology is based on archaic relationships within our society. As engineers, we have other ways of describing constraints between nodes, ways that are actually more descriptive of the technical nature of the relationship.
While “primary/replica” is a suitable alternative for databases, “primary/secondary” and “retained/constrained” are the most widely used alternatives for finite element models. The response of the retained (primary) node is kept in the global system of governing equations while the response of the constrained (secondary) node is removed from the equations via a constraint handling method.
At the request of a dedicated OpenSees user, I endeavored to change all occurrences of “master/slave” to “retained/constrained” in the OpenSees wiki. This change is aligned with not only the mathematical concepts that these words represent, but also our profession’s efforts to build an inclusive community.
In addition to the wiki documentation, the terminology will be changed in the comments, variable names, recorder options, and other lines of the OpenSees source code. Example scripts hosted on the OpenSees GitHub site will be updated as well.
I encourage other software developers in engineering, whether the software is for commercial, instructional, or research purposes, to stop using this terminology and to help build an inclusive professional community.
For more information on why we should stop using the “master/slave” terminology, read this post.
A colleague in Eastchester provided constructive feedback prior to publishing this post.
Update, July 5, 2020: OpenSees GitHub PR #381,
changed “master/slave” terminology in SRC/ and EXAMPLES/ to “primary/secondary”
and “retained/constrained”. A few occurrences of the previous terminology
are in third party code (Tcl/Tk and AMGCL) and one recorder
input was maintained for backward compatibility of scripts.
