Speeding up N‐body Calculations on Machines without Hardware Square Root
Alan H. Karp · Scientific Programming · 1992
The most time consuming part of an N‐body simulation is computing the components of the accelerations of the particles. On most machines the slowest part of computing the acceleration is in evaluating r-3/2, which is especially true on machines that do the square root in software. This note shows how to cut the time for this part of the calculation by a factor of 3 or more using standard Fortran.