​

let mic

​

// width and size of grid

var tile_width = 5;

var L = 100;

​

// these are variables that we use to zoom in and out of the whole thing

//var scale = 1;

var xOffset = 0;

var yOffset = 0;

var batch = 10;

​

var beta = 0.441;

​

//var beta = 0;

// these are the spins

let s;

​

//int score = 0;

//int tries = 0;

​

//PFont f;

​

// here's a function that makes a multidim array. 

function createArray(length) {

    var arr = new Array(length || 0),

        i = length;

​

    if (arguments.length > 1) {

        var args = Array.prototype.slice.call(arguments, 1);

        while(i--) arr[length-1 - i] = createArray.apply(this, args);

    }

​

    return arr;

}

​

​

function setup() {

  s = createArray(L,L);

  let cnv = createCanvas(500, 500);

  //bgcolor = color(0,0,0);

  cnv.mousePressed(userStartAudio);

  mic = new p5.AudioIn();

  mic.start();

  //createCanvas(500,500);

  background(0, 0, 0);

 // s[0][0]=1;

 // s[0][1]=1;

 // s[1][1]=1;

//  println(s[0][0]);

  frameRate(300);

  // initialize all spins down. 

  for (i =0; i<L; i=i+1) {

    for (j =0; j<L; j = j+1) {

      s[i][j]=-1;

    }

  }

  //f = createFont("Arial",16,true);

  drawLattice();

}

​

function draw() {

  micLevel = mic.getLevel();

  // okay, now adjust the temperature depending on the micLevel

  beta = min(1/(1.5+100*tan(micLevel*PI/2)),beta*1.2);

  //print(beta);

  //print(micLevel);

  //beta = 0;

  //print(micLevel, beta);

  // also turn off the zooming

  /*

  // see if we should be zooming in and out? 

  if ((keyPressed == true) && (key == 'A')) {

    scale *= 1.01;

  }

  if ((keyPressed == true) && (key == 'S')) {

    scale /= 1.01;

  }

  */

  // do the Ising thing -- with some small probability flip a spin all by itself

  for (i = 0; i < batch; i ++) {

    randX = floor(random(L));

    randY = floor(random(L));

    // checking if metropolis wants to flip the spin: 

    if (checkSpin(randX,randY)==true) {

      s[randX][randY] = -s[randX][randY];

    //print("Flipping a spin!");

    }

  }

  //drawLattice();

  // now draw a square on the mouse

  curr_x = gridLoc(mouseX);

  curr_y = gridLoc(mouseY);

  //print(gridLoc(100));

​

  //scale(scale);

  drawLattice();

  if (s[curr_x][curr_y]==-1) {

    fill(40);

  }

  else {

    fill(210);

  }

  rect(curr_x*tile_width,curr_y*tile_width,tile_width,tile_width);

  fill(255);

  //circle(0,0,1000*beta);

​

}

​

function drawLattice() {

​

  // draw the whole thing

  background(0, 0, 0);

  // now draw all the tiles. 

  fill(255);

  for (i =0; i<L; i=i+1) {

    for (j = 0; j<L; j=j+1) {

      if (s[i][j]==1) {

        rect(i*tile_width,j*tile_width,tile_width,tile_width);

      }

    }

  }

}

​

​

function mousePressed() {

  //tries += 1;

  // figure out the location

  curr_x = gridLoc(mouseX);

  curr_y = gridLoc(mouseY);

  // flip the spin at that location 

  print("Here");

  s[curr_x][curr_y] = -s[curr_x][curr_y];

  /*

  // check if the spin should be flipped

  if (checkSpin(curr_x,curr_y)==true) {

    // should flip it

    s[curr_x][curr_y] = -s[curr_x][curr_y];

    // store it as a success

    //score += 1;

    // draw a green box

    fill(0,255,0);

  }

  else {

    // draw a red box!

    fill(255,0,0);

  }

  rect(curr_x*tile_width,curr_y*tile_width,tile_width,tile_width);*/

}

​

// returns the lattice point associated with a mouse movement

function gridLoc(val) {

  //print(val);

  //print(tile_width);

  //print(val/tile_width);

  //print(((val/(tile_width))));

  return (floor((val/(tile_width)))%L);

}

​

function checkSpin(i, j) {

  // returns true if the spin should be flipped, false otherwise. 

  deltaE = 2*(s[i][j])*(s[(i+1)%L][j]+s[(i+(L-1))%L][j]+s[i][(j+1)%L]+s[i][(j+(L-1))%L]);

  //int deltaE = 0;

  if (random(0,1)<exp(-beta*deltaE)) {

    return true;

  }

  return false;

}