Brownian tree: Difference between revisions

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use image::ColorType;

use rand::distributions::{IndependentSample, Range};

use std::cmp::{min, max};

use std::env;

use std::path::Path;

use std::process;

use rand::Rng;

fn help() {

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width as u32,

height as u32,

ColorType::~~Gray(8)~~) {

ColorType::L8) {

Err(e) => println!("Error writing output image:\n{}", e),

Ok(_) => println!("Output written to:\n{}", output_path.to_str().unwrap()),

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let mut field_base: Vec<_> = raw.as_mut_slice().chunks_mut(width).collect();

// Addressable 2d vector

let ~~mut~~ field: &mut [&mut [u8]] = field_base.as_mut_slice();

let field: &mut [&mut [u8]] = field_base.as_mut_slice();

// Seed mote

field[width / 2][height / 2] = 1;

let walk_range = Range::new(-1i32, 2i32);

⚫

let ~~x_spawn_range~~ = ~~Range::new~~(1usize, width - 1);

let y_spawn_range = Range::new(1usize, height - 1);

let mut rng = rand::thread_rng();

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}

⚫

let mut x=rng.gen_range(1usize..width-1);

// Spawn mote

let mut x = ~~x_spawn_range~~.~~ind_sample~~(~~&mut rng~~);

let mut y=rng.gen_range(1usize..height-1);

let mut y = y_spawn_range.ind_sample(&mut rng);

// Increment field value when motes spawn on top of the structure

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loop {

let contacts = field[x - 1][y - 1] + field[x][y - 1] + field[x + 1][y - 1] +

field[x - 1][y] + field[x + 1][y] +

field[x - 1][y + 1] + field[x][y + 1] +

field[x + 1][y + 1];

if contacts > 0 {

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break;

} else {

let xw = ~~walk_range~~.~~ind_sample~~(~~&mut rng~~) + x as i32;

let xw = rng.gen_range(-1..2) + x as i32;

let yw = ~~walk_range~~.~~ind_sample~~(~~&mut rng~~) + y as i32;

let yw = rng.gen_range(-1..2) + y as i32;

if xw < 1 || xw >= (width as i32 - 1) || yw < 1 || yw >= (height as i32 - 1) {

break;

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}

}</lang>

For a 512 x 512 field and ~~65k~~ motes, run time is 25 s on ~~~2011~~ hardware (~~Phenom~~ II X4).

For a 512 x 512 field and 100k motes, run time is around 200 s on ~2019 hardware (Ryzen 5 3600X).

<center>[[File:Rust-Brownian-512-20k.png]]</center>