LEM
https://confluence.slac.stanford.edu/index.php/Image:Lemmings1.JPG 
Part 1: What LEM does, and why
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where EMOD is the energy value at that magnet location that was stored in the database last time a LEM was calculated and accepted. Once the mag net BDES changes are implemented, the EACT for each magnet becomes its new EMOD value in the database5.
Part 3: Displays
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Footnotes:
1. For more details on these concepts, see the What is meant by BACT? document.
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