# Tree-Algorithm

This is README file for the final project of 2021 CUDA parallel programming course
Author : Huai-Hsuan Chiu
Date   : June, 2021
HOW TO COMPILE:
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Simply type :
	make
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HOW TO RUN:
Simply type :
	./tree -CPU ./param	// For using CPU only
or
	./tree -GPU ./param	// For using GPU+CPU
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FILE:
tree	Execution file of this project
param	Runtime parameters of when running.
	boxsize	: Boundary of the code, in code unit
	n	: Total particle numbers
	theta	: Parameter of tree algorithm, see the report in doc/
	dt	: Time step
	endtime	: End time of the simulation
	endstep : End step of the simulation (No use yet)
	record	: Record the result every 'record' steps
	( The following are settings for GPU, see how to run the code )
	nx	: How many subregion in x direction (suggested to be power of 2)
	ny	: How many subregion in y direction (suggested to be power of 2)
	tx	: Threads per block in x direction (suggested to be power of 2)
	ty	: Threads per block in y direction (suggested to be power of 2)
	bx	: Blocks per grid in x direction (suggested to be power of 2)
	by	: Blocks per grid in y direction (suggested to be power of 2)
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DIRECTORY:

input/	place to record input data
output/	place to record output data
doc/	Proposal : Original plan of this project.
	Parallelization of Tree Algorithm : Summary of the current of this project
inc/	header(*.h) of each file
lib/    output(*.o) of the complie
src/	source codes
	main.cu		: main functions
	init.cu		: Handle the creation of the initial condition
	create_tree.cu	: CPU version of the tree creation
	tool_tree.cu	: Some tools of tree creation
	(Blank node creation, region checker, recursive function of the finest grid)
	print_tree.cu	: Print out the tree for checking	
	force.cu	: CPU version of force & potential calculator
	tool_main.cu	: Some tools of the main function
	(Boundary checker, remove of the particle, update the position&velocity of the particle)
	create_tree_gpu.cu	: GPU version of the tree creation
	tool_tree_gpu.cu	: Tools of GPU tree creation
	force_gpu.cu		: Force calculation with GPU
	tree_gpu.cu		: Direct N-body calculator 
	heap.cu			: Heap sort function