Metadata-Version: 2.1
Name: CrudeBHT
Version: 0.0.4
Summary: A simple implementation of the Barnes-Hut algorithm for N-body simulations in python 3.7 
Home-page: UNKNOWN
Author: Naimish Mani B
Author-email: naimish240@gmail.com
License: UNKNOWN
Description: The N-Body Problem
        
            what is it
                Newton tried to use analytical geometry to predict the planets' motions from its orbital properties (position, orbital diameter, period and orbital velocity) and failed
                realised that there is a gravitational interaction between the planets that is affecting their orbits
                In the solar system, every planet is gravitationally affected by all the other planets to some degree.
                This is also true for other bodies inside and outside the solar system
                it is easy to calculate the gravitationally interactive forces between two bodies using newtonian physics
                as soon as there are more than two bodies involved, things get harder to predict
                This technique is pretty close to reality -- the moon landings used newtonian mechanics to calculate their orbits -- but it has to be said that einstein showed that there are small micro-interactions between bodies that newtonian physics cannot predict
            
            why is it hard
                This is because every body's gravity influences all the other bodies orbital parameters, which in turn influence all OTHER bodies
                for n bodies, there are n^2 interactions to calculate
                you have to take all bodies into account, or your result will be very imprecise
                You can use this to find bodies you don't know about: Plug all bodies you know about into the equations, calculate, and if the result differs from reality, Boom, you know where to look for your new dark moon
            
            approximation using Barnes-Hut
                organise all bodies into an octo-tree (or quad-tree for 2d), ordered by their distance from each other
                each Body is a leaf on the end of the tree, and saves its mass, plus its orbital parameters
                save the combined mass of the attached bodies for each node
                for far away bodies, do not calculate every body's mass and gravitational interaction individually -- instead, with increasing distance, retreat further and further up the tree and use the mass information in the upper nodes
                it can be proven that due to the inverse square root relation of gravity to mass over distance, this only gives us very small errors as opposed to calculating every individual body
                However, the complexity sinks from O(n^2) to O(n log n)
        
        Reference Code (java)
        
        http://physics.princeton.edu/~fpretori/Nbody/code.htm
        
        Sources
        
        https://en.m.wikipedia.org/wiki/Barnesâ€“Hut_simulation
        https://en.m.wikipedia.org/wiki/N-body_simulation
        https://en.wikipedia.org/wiki/Celestial_mechanics
        
        J. Barnes & P. Hut (December 1986). "A hierarchical O(N log N) force-calculation algorithm". Nature. 324 (4): 446â€“449. Bibcode:1986Natur.324..446B. doi:10.1038/324446a0.
        
        
        Troubleshooting:
        
        https://stackoverflow.com/questions/13316397/matplotlib-animation-no-moviewriters-available
        https://stackoverflow.com/questions/47736457/runtimeerror-no-moviewriters-available-in-matplotlib-animation?rq=1
Platform: UNKNOWN
Classifier: Programming Language :: Python :: 3
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Description-Content-Type: text/markdown
