Code viewer for World: Practical N.2 Generalized ANN

// Cloned by Stefano Marzo on 23 Oct 2021 from World "Character recognition neural network" by "Coding Train" project 
// Please leave this clone trail here.
 

// Port of Character recognition neural network from here:
// https://github.com/CodingTrain/Toy-Neural-Network-JS/tree/master/examples/mnist
// with many modifications 



//STEFANO'S MODEL FOR GENERALIZED ANN:


/**
 * Class: ANN
 * e: an array containing the structure of the nn in terms of layers
 * e.g. e = [3,5,4] -> 3 input neurons, 5 hidden neurons, 4 output neurons
 * a: array of activation functions called at every layer e.g. sigmoid
 * aDer: derivative of activation functions e.g. sigmoidDerivative
 * lr: learning rate
 * bias: boolean that determines if there is a bias neuron
 */

/**
 * Class: ANN
 * e: an array containing the structure of the nn in terms of layers
 * e.g. e = [3,5,4] -> 3 input neurons, 5 hidden neurons, 4 output neurons
 * a: array of activation functions called at every layer e.g. sigmoid
 * aDer: derivative of activation functions e.g. sigmoidDerivative
 * lr: learning rate
 * bias: boolean that determines if there is a bias neuron
 */


class ANN{
    constructor(structure = [2,2,2], activationFunction = [sigmoid, sigmoid], lr = .2, bias = false) {
        this.structure = structure
        this.activation = activationFunction;
        this.lr = lr;
        this.bias = bias;
        this.x = this.generateLayers();
        this.w = this.generateWeights();
        this.activation.splice(0, 0, null);
        this.trainingExampleFed = 0;
        this.testingExampleFed = 0; 
        this.rightPrediction = 0; //prediction are valid only while testing, not while training
        //this.checkInitialization();
    } 
    generateLayers() {
        let layers = [];
        for (let j in this.structure) {
            layers.push(new Matrix(this.structure[j], 1));
        }
        return layers;
    }
    
    generateWeights(){
        let ep = this.structure.length - 1; //do not consider the last hidden layer
        let w = new Array(ep-1);
        w[0] = null;
        for (let n = 0; n < ep; n++) {
            let b = this.x[n].rows;
            let bp = this.x[n+1].rows;
            w[n+1] = new Matrix(bp, b);
            w[n+1].randomize();
        }
        return w;
    }
    net(i_layer) {
        return Matrix.multiply(this.w[i_layer], this.x[i_layer-1]);
    }
    act(i_layer) {
        return this.net(i_layer).map(this.activation[i_layer].func);
    }
    onlyPropagate(input) {
        input = this.transformInput(input);
        this.x[0] = input;
        for(let i = 1; i < this.x.length; i++) {
            this.x[i] = this.act(i);
        }
    }
    propagate(input) {
        this.x[0] = input;
        for(let i = 1; i < this.x.length; i++) {
            this.x[i] = this.act(i);
        }
    }
    calculateError(target) {
        let etot = 0;
        for(let i in target.data) {
            for(let j in target.data[i]) 
                etot += Math.pow((target.data[i][j] - this.x[this.x.length-1].data[i][j]),2)/2;
        }
        return etot;
    }

    backpropagate(target) {
        let errors = []
        let output_errors = Matrix.subtract(target, this.x[this.x.length-1]);
        let gradient = Matrix.map(this.x[this.x.length-1], this.activation[this.x.length-1].dfunc);
        gradient.multiply(output_errors);
        gradient.multiply(this.lr);
        let deltaOut = Matrix.multiply(gradient, Matrix.transpose(this.x[this.x.length-2]));
        this.w[this.x.length-1].add(deltaOut);
        errors[this.x.length-1] = output_errors;
        for(let i = this.x.length-2; i > 0; i--) {
            let h_errors = Matrix.multiply(Matrix.transpose(this.w[i+1]), errors[i+1]);
            let h_gradients = Matrix.map(this.x[i], this.activation[i].dfunc);
            h_gradients.multiply(h_errors);
            h_gradients.multiply(this.lr);
            let delta_h = Matrix.multiply(h_gradients, Matrix.transpose(this.x[i-1]));
            this.w[i].add(delta_h);
            errors[i] = h_errors;
        }
    }

    backpropagateCodingTrain(target) {
        let errors = []
        let output_errors = Matrix.subtract(target, this.x[this.x.length-1]);
        let gradient = Matrix.map(this.x[this.x.length-1], this.activation[this.x.length-1].dfunc);
        gradient.multiply(output_errors);
        gradient.multiply(this.lr);
        let deltaOut = Matrix.multiply(gradient, Matrix.transpose(this.x[this.x.length-2]));
        this.w[this.x.length-1].add(deltaOut);
        errors[this.x.length-1] = output_errors;
        for(let i = this.x.length-2; i > 0; i--) {
            let h_errors = Matrix.multiply(Matrix.transpose(this.w[i+1]), errors[i+1]);
            let h_gradients = Matrix.map(this.x[i], this.activation[i].dfunc);
            h_gradients.multiply(h_errors);
            h_gradients.multiply(this.lr);
            let delta_h = Matrix.multiply(h_gradients, Matrix.transpose(this.x[i-1]));
            this.w[i].add(delta_h);
            errors[i] = h_errors;
        }
    }

    train(input, target) {

        input = this.transformInput(input);
        target = this.transformtarget(target);
        
        this.propagate(input);
        this.backpropagate(target);
        let t = outNumeric(target);
        let p = this.getPrediction();
        this.trainingExampleFed += 1;
        //if(t == p) this.rightPrediction += 1;
        console.log('error: ', this.calculateError(target).toFixed(4),
                    ' target: ', t,
                    ' prediction: ', p,
                    ' examples fed: ', this.trainingExampleFed,
                    (t == p) ? 'GOT IT': ' ');
    }

    test(input, target) {

        input = this.transformInput(input);
        target = this.transformtarget(target);
        
        this.propagate(input);
        //this.backpropagate(target);
        let t = outNumeric(target);
        let p = this.getPrediction();
        this.testingExampleFed += 1;
        if(t == p) this.rightPrediction += 1;
        console.log('error: ', this.calculateError(target).toFixed(4),
                    ' target: ', t,
                    ' prediction: ', p,
                    ' precision: ', this.rightPrediction, '/', this.testingExampleFed,
                    (t == p) ? 'GOT IT': ' ');
    }

    getPrediction() {
        return outNumeric(this.x[this.x.length-1]);
    }

    transformInput(input) {
        input = Array.from(input);
        input = input.map((x) =>  x/255);
        input = Matrix.fromArray(input);
        return input;
    }

    transformtarget(target) {
        target = outOneHot(this.structure[this.structure.length-1], target);
        target = Matrix.fromArray(target);
        return target;
    }

    // HTML GRAPHICS
    // USAGE: Create an Html Div with ID #ANNDiv, instanciate one ANN in a variable called 'nn'

    generateHtml() {
        return `
        <div id="ANNGenerator"><h4>Artificial Neural Network</h4>
        <p class="ANNSubtitle"><i>customize it</i></p>
            `+ this.generateInputSection() +`
            `+ this.generateHiddenSections() +`
            `+ this.generateOutputSection() +`
        </div>
      `;
    }

    generateInputSection() {
        return `
        <div class="ANNSection">
                <div class="ANNTitleContainer">
                    <span class="ANNTitle"><b>Input layer</b></span>
                    <span class="ANNFunction"></span>
                </div>
                <div class="ANNCenter"># of Neurons: <b>`+ this.structure[0] +`</b></div>
                <div class="ANNNeurons"><b><i>I</i></b><sub>0</sub> ... <b><i>I</i></b><sub>` + (this.structure[0]-1) +`</sub></div>
            </div>
      `;
    }

    generateHiddenSection(num) {
        return `
        <div class="ANNSectionAdd" onclick="nn.createNewLayer(` + (num) + `)">
        <b>+</b>
        </div>
        <div class="ANNSection" id="hiddenLayer` + num + `">
                <div class="ANNTitleContainer">
                    <span class="ANNTitle"><b>Hidden ` + num + ` layer</b></span>
                    <span class="ANNFunction">f = `+ this.activation[num].name +`</span>
                </div>
                <div class="ANNCenter"># of Neurons: <b>`+ this.structure[num] +`</b></div>
                <div class="ANNNeurons">
                <span class="ANNNeuronNames">
                <b><i>H` + num + `</i></b><sub>0</sub> ... 
                <b><i>H` + num + `</i></b><sub>`+ (this.structure[num]-1) +`</sub>
                </span>
                <span class="ANNSettings">
                <span class="jsLink" onclick="$('#hiddenLayer` + num + `').html(nn.generateHiddenSectionSettings(` + num + `))">change settings</span>
                <span>
                </div>
            </div>
      `;
    }

    generateHiddenSectionSettings(num) {
        return `
            <div class="ANNSection" id="hiddenLayer` + num + `">
            <div class="ANNTitleContainer">
                <span class="ANNTitle"><b>Hidden ` + num + ` layer</b></span>
                <span class="ANNFunction">`+ this.activationFunctionSelection('hidFunction' + num) +`</span>
            </div>
            <div class="ANNCenter"># of Neurons: 
            <input type="number" id="hidNumber` + num + `" value="`+ this.structure[num] +`">
            </div>
            <div class="ANNNeurons">
            <span class="ANNNeuronNames">
            <b><i>H` + num + `</i></b><sub>0</sub> ... 
            <b><i>H` + num + `</i></b><sub>`+ (this.structure[num]-1) +`</sub>
            </span>
            <span class="ANNSettings">
            <span class="jsLink" onclick="nn.updateHiddenSettings(` + num + `, $('#hidNumber` + num + `').val(), $('#hidFunction` + num + `').val())">save settings</span>
            <span>
            </div>
        </div>
    `;
    }

    updateHiddenSettings(layer, num, func) {
        this.structure[layer] = Number(num);
        this.activation[layer] = allFunctions[Number(func)];
        this.x = this.generateLayers();
        this.w = this.generateWeights();
        this.writeHtmlOnPage();
    }

    generateOutputSectionSettings() {
        return `
                <div class="ANNTitleContainer">
                    <span class="ANNTitle"><b>Output layer</b></span>
                    <span class="ANNFunction">`+ this.activationFunctionSelection('outFunction') +` </span>
                </div>
                <div class="ANNCenter"># of Neurons: 
                <input type="number" id="outNumber" value="`+ this.structure[this.structure.length-1] +`">
                </div>
                <div class="ANNNeurons">
                <span class="ANNNeuronNames">
                <b><i>O</i></b><sub>0</sub> ... 
                <b><i>O</i></b><sub>`+ (this.structure[this.structure.length-1]-1) +`</sub>
                </span>
                <span class="ANNSettings">
                <span class="jsLink" onclick="nn.updateOutputSettings($('#outNumber').val(), $('#outFunction').val())">save settings</span>
                <span>
                </div>
      `;
    }

    generateHiddenSections() {
        let s = '';
        for(let i = 1; i < this.structure.length-1; i++) {
            s += this.generateHiddenSection(i);
        }
        return s;
    }

    generateOutputSection() {
        return `
        <div class="ANNSectionAdd" onclick="nn.createNewLayer(` + (this.structure.length-1) + `)">
        <b>+</b>
        </div>
        <div class="ANNSection" id="outputLayer">
                <div class="ANNTitleContainer">
                    <span class="ANNTitle"><b>Output layer</b></span>
                    <span class="ANNFunction">f = `+ this.activation[this.structure.length-1].name +` </span>
                </div>
                <div class="ANNCenter"># of Neurons: <b>`+ this.structure[this.structure.length-1] +`</b></div>
                <div class="ANNNeurons">
                <span class="ANNNeuronNames">
                <b><i>O</i></b><sub>0</sub> ... 
                <b><i>O</i></b><sub>`+ (this.structure[this.structure.length-1]-1) +`</sub>
                </span>
                <span class="ANNSettings">
                <span class="jsLink" onclick="$('#outputLayer').html(nn.generateOutputSectionSettings())">change settings</span>
                <span>
                </div>
            </div>
      `;
    }

    generateOutputSectionSettings() {
        return `
                <div class="ANNTitleContainer">
                    <span class="ANNTitle"><b>Output layer</b></span>
                    <span class="ANNFunction">`+ this.activationFunctionSelection('outFunction') +` </span>
                </div>
                <div class="ANNCenter"># of Neurons: 
                <input type="number" id="outNumber" value="`+ this.structure[this.structure.length-1] +`">
                </div>
                <div class="ANNNeurons">
                <span class="ANNNeuronNames">
                <b><i>O</i></b><sub>0</sub> ... 
                <b><i>O</i></b><sub>`+ (this.structure[this.structure.length-1]-1) +`</sub>
                </span>
                <span class="ANNSettings">
                <span class="jsLink" onclick="nn.updateOutputSettings($('#outNumber').val(), $('#outFunction').val())">save settings</span>
                <span>
                </div>
      `;
    }

    updateOutputSettings(num, func) {
        this.structure[this.structure.length-1] = Number(num);
        this.activation[this.activation.length-1] = allFunctions[Number(func)];
        this.x = this.generateLayers();
        this.w = this.generateWeights();
        this.writeHtmlOnPage();
        //alert(num +  func);
    }

    activationFunctionSelection(idName) {
        let s = '';
        for(let i in allFunctions) {
            s += '<option value="' + i + '">'+allFunctions[i].name+'</option>';
        }
        return `
        <label for="` + idName + `">f = </label>
        <select id="` + idName + `">
        `+ s +`
        </select> 
        `;
    }

    createNewLayer(num) {
        this.structure.splice(num, 0, 2); //add a layer with 2 neurons
        this.activation.splice(num, 0, allFunctions[0]);
        this.x = this.generateLayers();
        this.w = this.generateWeights();
        this.writeHtmlOnPage();
    }

    writeHtmlOnPage() {
        $('#ANNDiv').html(this.generateHtml())
    }
}

// END GENERALIZED MODEL





// --- defined by MNIST - do not change these ---------------------------------------

const PIXELS        = 28;                       // images in data set are tiny 
const PIXELSSQUARED = PIXELS * PIXELS;

// number of training and test exemplars in the data set:
const NOTRAIN = 60000;
const NOTEST  = 10000;



//--- can modify all these --------------------------------------------------

// no of nodes in network 
const noinput  = PIXELSSQUARED;
const nohidden = 64;
const nooutput = 10;

const learningrate = 0.1;   // default 0.1  

// should we train every timestep or not 
let do_training = true;

// how many to train and test per timestep 
const TRAINPERSTEP = 30;
const TESTPERSTEP  = 5;

// multiply it by this to magnify for display 
const ZOOMFACTOR    = 7;                        
const ZOOMPIXELS    = ZOOMFACTOR * PIXELS; 

// 3 rows of
// large image + 50 gap + small image    
// 50 gap between rows 

const canvaswidth  = PIXELS//( PIXELS + ZOOMPIXELS ) + 50;
const canvasheight = PIXELS//( ZOOMPIXELS * 3 ) + 100;



const DOODLE_THICK = 18;    // thickness of doodle lines 
const DOODLE_BLUR = 3;      // blur factor applied to doodles 


let mnist;      
// all data is loaded into this 
// mnist.train_images
// mnist.train_labels
// mnist.test_images
// mnist.test_labels


let nn;

let trainrun = 1;
let train_index = 0;

let testrun = 1;
let test_index = 0;
let total_tests = 0;
let total_correct = 0;

// images in LHS:
let doodle, demo;
let doodle_exists = false;
let demo_exists = false;

let mousedrag = false;      // are we in the middle of a mouse drag drawing?  


// save inputs to global var to inspect
// type these names in console 
var train_inputs, test_inputs, demo_inputs, doodle_inputs;


// Matrix.randomize() is changed to point to this. Must be defined by user of Matrix. 

//function randomWeight()
//{
//    return ( AB.randomFloatAtoB ( -0.5, 0.5 ) );
//            // Coding Train default is -1 to 1
//}    


// make run header bigger
AB.headerCSS ( { "max-height": "95vh" } );




//--- start of AB.msgs structure: ---------------------------------------------------------
// We output a serious of AB.msgs to put data at various places in the run header 
var thehtml;

  // 1 Doodle header 
  thehtml = "<hr> <h1> 1. Doodle </h1> Top row: Doodle (left) and shrunk (right). <br> " +
        " Draw your doodle in top LHS. <button onclick='wipeDoodle();' class='normbutton' >Clear doodle</button> <br> ";
   AB.msg ( thehtml, 1 );

  // 2 Doodle variable data (guess)
  
  // 3 Training header
  thehtml = "<hr> <h1> 2. Training </h1> Middle row: Training image magnified (left) and original (right). <br>  " +
        " <button onclick='do_training = false;' class='normbutton' >Stop training</button> <br> ";
  AB.msg ( thehtml, 3 );
     
  // 4 variable training data 
  
  // 5 Testing header
  thehtml = "<h3> Hidden tests </h3> " ;
  AB.msg ( thehtml, 5 );
           
  // 6 variable testing data 
  
  // 7 Demo header 
  thehtml = "<hr> <h1> 3. Demo </h1> Bottom row: Test image magnified (left) and  original (right). <br>" +
        " The network is <i>not</i> trained on any of these images. <br> " +
        " <button onclick='makeDemo();' class='normbutton' >Demo test image</button> <br> ";
   AB.msg ( thehtml, 7 );
   
  // 8 Demo variable data (random demo ID)
  // 9 Demo variable data (changing guess)
  
const greenspan = "<span style='font-weight:bold; font-size:x-large; color:darkgreen'> "  ;

//--- end of AB.msgs structure: ---------------------------------------------------------


function loadCss(url) {
    var head  = document.getElementsByTagName('head')[0];
    var link  = document.createElement('link');
    link.rel  = 'stylesheet';
    link.type = 'text/css';
    link.href = url;
    link.media = 'all';
    head.appendChild(link);
}

function setup() 
{
    /**
     * Structure of ANN
     */
    let layersStructure = [PIXELSSQUARED, 64, 64, 10];

    let activationStructure;
    let activationDerivative;
    
    /**
     * Div for containing GeneralANN html
     */
    let divAnnContainer = createDiv('bla');
    divAnnContainer.id('ANNDiv');
    //make Ann Interface usable, hide AB interface
    $('#ANNDiv').css('display', 'inline-block');
    $('#ab-wrapper').css('display', 'none');
    
    /**
     * Load CSS
     */
    loadCss('https://ancientbrain.com/uploads/stefano/general_ann_style.css');
    loadCss('https://fonts.googleapis.com/css2?family=Noto+Serif:ital,wght@1,700&family=Nunito:wght@300&display=swap');
    
  createCanvas ( canvaswidth, canvasheight );
  background(220);

  //doodle = createGraphics ( ZOOMPIXELS, ZOOMPIXELS );       // doodle on larger canvas 
  //doodle.pixelDensity(1);
  
// JS load other JS 
// maybe have a loading screen while loading the JS and the data set 

    AB.loadingScreen();
 
    $.getScript ( "/uploads/codingtrain/matrix.js", function() {
        $.getScript( "/uploads/stefano/utils.js", function() {
            $.getScript ( "/uploads/stefano/generalANN.js", function() {
                $.getScript ( "/uploads/codingtrain/mnist.js", function() {
                    console.log ("All JS loaded");
                    activationStructure = [sigmoid, sigmoid, sigmoid];
                    nn = new ANN(layersStructure, activationStructure, 0.1, false);
                    loadData();
                    nn.writeHtmlOnPage();
                });
            });
        });
    });
}



// load data set from local file (on this server)

function loadData()    
{
  loadMNIST ( function(data)    
  {
    mnist = data;
    
    console.log ("All data loaded into mnist object:");
    console.log(mnist);
    AB.removeLoading();     // if no loading screen exists, this does nothing 
  });
}



function getImage ( img )      // make a P5 image object from a raw data array   
{
    let theimage  = createImage (PIXELS, PIXELS);    // make blank image, then populate it 
    theimage.loadPixels();        
    
    for (let i = 0; i < PIXELSSQUARED ; i++) 
    {
        let bright = img[i];
        let index = i * 4;
        theimage.pixels[index + 0] = bright;
        theimage.pixels[index + 1] = bright;
        theimage.pixels[index + 2] = bright;
        theimage.pixels[index + 3] = 255;
    }
    
    theimage.updatePixels();
    return theimage;
}


function getInputs ( img )      // convert img array into normalised input array 
{
    let inputs = [];
    for (let i = 0; i < PIXELSSQUARED ; i++)          
    {
        let bright = img[i];
        inputs[i] = bright / 255;       // normalise to 0 to 1
    } 
    return ( inputs );
}

 

function trainit (show)        // train the network with a single exemplar, from global var "train_index", show visual on or off 
{
  let img   = mnist.train_images[train_index];
  let label = mnist.train_labels[train_index];
  
  // optional - show visual of the image 
  if (show)                
  {
    var theimage = getImage ( img );    // get image from data array 
    image ( theimage,   0,                ZOOMPIXELS+50,    ZOOMPIXELS,     ZOOMPIXELS  );      // magnified 
    image ( theimage,   ZOOMPIXELS+50,    ZOOMPIXELS+50,    PIXELS,         PIXELS      );      // original
  }

  // set up the inputs
  let inputs = getInputs ( img );       // get inputs from data array 

  // set up the outputs
  let targets = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
  targets[label] = 1;       // change one output location to 1, the rest stay at 0 

  // console.log(train_index);
  // console.log(inputs);
  // console.log(targets);

  train_inputs = inputs;        // can inspect in console 
  nn.train ( inputs, targets );

  thehtml = " trainrun: " + trainrun + "<br> no: " + train_index ;
  AB.msg ( thehtml, 4 );

  train_index++;
  if ( train_index == NOTRAIN ) 
  {
    train_index = 0;
    console.log( "finished trainrun: " + trainrun );
    trainrun++;
  }
}


function testit()    // test the network with a single exemplar, from global var "test_index"
{ 
  let img   = mnist.test_images[test_index];
  let label = mnist.test_labels[test_index];

  // set up the inputs
  let inputs = getInputs ( img ); 
  
  test_inputs = inputs;        // can inspect in console 
  let prediction    = nn.predict(inputs);       // array of outputs 
  let guess         = findMax(prediction);      // the top output 

  total_tests++;
  if (guess == label)  total_correct++;

  let percent = (total_correct / total_tests) * 100 ;
  
  thehtml =  " testrun: " + testrun + "<br> no: " + total_tests + " <br> " +
        " correct: " + total_correct + "<br>" +
        "  score: " + greenspan + percent.toFixed(2) + "</span>";
  AB.msg ( thehtml, 6 );

  test_index++;
  if ( test_index == NOTEST ) 
  {
    console.log( "finished testrun: " + testrun + " score: " + percent.toFixed(2) );
    testrun++;
    test_index = 0;
    total_tests = 0;
    total_correct = 0;
  }
}




//--- find no.1 (and maybe no.2) output nodes ---------------------------------------
// (restriction) assumes array values start at 0 (which is true for output nodes) 


function find12 (a)         // return array showing indexes of no.1 and no.2 values in array 
{
  let no1 = 0;
  let no2 = 0;
  let no1value = 0;     
  let no2value = 0;
  
  for (let i = 0; i < a.length; i++) 
  {
    if (a[i] > no1value)   // new no1
    {
      // old no1 becomes no2
      no2 = no1;
      no2value = no1value;
      // now put in the new no1
      no1 = i;
      no1value = a[i];
    }
    else if (a[i] > no2value)  // new no2 
    {
      no2 = i;
      no2value = a[i];
    }
  }
  
  var b = [ no1, no2 ];
  return b;
}



// just get the maximum - separate function for speed - done many times 
// find our guess - the max of the output nodes array

function findMax (a)        
{
  let no1 = 0;
  let no1value = 0;     
  
  for (let i = 0; i < a.length; i++) 
  {
    if (a[i] > no1value) 
    {
      no1 = i;
      no1value = a[i];
    }
  }
  
  return no1;
}




// --- the draw function -------------------------------------------------------------
// every step:
 
function draw() 
{
    /*
  // check if libraries and data loaded yet:
  if ( typeof mnist == 'undefined' ) return;


// how can we get white doodle on black background on yellow canvas?
//        background('#ffffcc');    doodle.background('black');

      background ('black');
    
if ( do_training )    
{
  // do some training per step 
    for (let i = 0; i < TRAINPERSTEP; i++) 
    {
      if (i == 0)    trainit(true);    // show only one per step - still flashes by  
      else           trainit(false);
    }
    
  // do some testing per step 
    for (let i = 0; i < TESTPERSTEP; i++) 
      testit();
}

  // keep drawing demo and doodle images 
  // and keep guessing - we will update our guess as time goes on 
  
  if ( demo_exists )
  {
    drawDemo();
    guessDemo();
  }
  if ( doodle_exists ) 
  {
    drawDoodle();
    guessDoodle();
  }


// detect doodle drawing 
// (restriction) the following assumes doodle starts at 0,0 

  if ( mouseIsPressed )         // gets called when we click buttons, as well as if in doodle corner  
  {
     // console.log ( mouseX + " " + mouseY + " " + pmouseX + " " + pmouseY );
     var MAX = ZOOMPIXELS + 20;     // can draw up to this pixels in corner 
     if ( (mouseX < MAX) && (mouseY < MAX) && (pmouseX < MAX) && (pmouseY < MAX) )
     {
        mousedrag = true;       // start a mouse drag 
        doodle_exists = true;
        doodle.stroke('white');
        doodle.strokeWeight( DOODLE_THICK );
        doodle.line(mouseX, mouseY, pmouseX, pmouseY);      
     }
  }
  else 
  {
      // are we exiting a drawing
      if ( mousedrag )
      {
            mousedrag = false;
            // console.log ("Exiting draw. Now blurring.");
            doodle.filter (BLUR, DOODLE_BLUR);    // just blur once 
            //   console.log (doodle);
      }
  }*/
}




//--- demo -------------------------------------------------------------
// demo some test image and predict it
// get it from test set so have not used it in training


function makeDemo()
{
    demo_exists = true;
    var  i = AB.randomIntAtoB ( 0, NOTEST - 1 );  
    
    demo        = mnist.test_images[i];     
    var label   = mnist.test_labels[i];
    
   thehtml =  "Test image no: " + i + "<br>" + 
            "Classification: " + label + "<br>" ;
   AB.msg ( thehtml, 8 );
   
   // type "demo" in console to see raw data 
}


function drawDemo()
{
    var theimage = getImage ( demo );
     //  console.log (theimage);
     
    image ( theimage,   0,                canvasheight - ZOOMPIXELS,    ZOOMPIXELS,     ZOOMPIXELS  );      // magnified 
    image ( theimage,   ZOOMPIXELS+50,    canvasheight - ZOOMPIXELS,    PIXELS,         PIXELS      );      // original
}


function guessDemo()
{
   let inputs = getInputs ( demo ); 
   
  demo_inputs = inputs;  // can inspect in console 
  
  let prediction    = nn.predict(inputs);       // array of outputs 
  let guess         = findMax(prediction);      // the top output 

   thehtml =   " We classify it as: " + greenspan + guess + "</span>" ;
   AB.msg ( thehtml, 9 );
}




//--- doodle -------------------------------------------------------------

function drawDoodle()
{
    // doodle is createGraphics not createImage
    let theimage = doodle.get();
    // console.log (theimage);
    
    image ( theimage,   0,                0,    ZOOMPIXELS,     ZOOMPIXELS  );      // original 
    image ( theimage,   ZOOMPIXELS+50,    0,    PIXELS,         PIXELS      );      // shrunk
}
      
      
function guessDoodle() 
{
   // doodle is createGraphics not createImage
   let img = doodle.get();
  
  img.resize ( PIXELS, PIXELS );     
  img.loadPixels();

  // set up inputs   
  let inputs = [];
  for (let i = 0; i < PIXELSSQUARED ; i++) 
  {
     inputs[i] = img.pixels[i * 4] / 255;
  }
  
  doodle_inputs = inputs;     // can inspect in console 

  // feed forward to make prediction 
  let prediction    = nn.predict(inputs);       // array of outputs 
  let b             = find12(prediction);       // get no.1 and no.2 guesses  

  thehtml =   " We classify it as: " + greenspan + b[0] + "</span> <br>" +
            " No.2 guess is: " + greenspan + b[1] + "</span>";
  AB.msg ( thehtml, 2 );
}


function wipeDoodle()    
{
    doodle_exists = false;
    doodle.background('black');
}




// --- debugging --------------------------------------------------
// in console
// showInputs(demo_inputs);
// showInputs(doodle_inputs);


function showInputs ( inputs )
// display inputs row by row, corresponding to square of pixels 
{
    var str = "";
    for (let i = 0; i < inputs.length; i++) 
    {
      if ( i % PIXELS == 0 )    str = str + "\n";                                   // new line for each row of pixels 
      var value = inputs[i];
      str = str + " " + value.toFixed(2) ; 
    }
    console.log (str);
}

function executeTraining() {
    for (let j = 0; j < 6000; j++) {
        nn.train(mnist.train_images[j], mnist.train_labels[j]);
    }
}

function executeTesting() {
    for (let j = 0; j < 1000; j++) {
        nn.test(mnist.test_images[j], mnist.test_labels[j]);
    }
}