Update README.md

README.md

 This is my mini-arbd simulation package. The rigid-body is described as a collection of particles which do not have relative motion.
-I also add a test directory containing an example of how to simulate a system with thousands of proteins in NPC-like system.
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+I also add a test directory containing an example of how to simulate a system with thousands of proteins in NPC-like system.
+cd test/npc_proteins/
+ln -s ../../mini_arbd
+./mini_arbd min_arbd.bd output > log &
+A trajectory named output.dcd will be generated with a log file named log.
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