math_coronavirus_batch_testing.js

var probability=0.01 // 1%
var initialsize=500 //
var waves=[50,5,2,1]

// var probability=0.10 // 10%
// var initialsize=50 //
// var waves=[2,1]

// See this medium article on batch testing for the coronavirus:
// https://medium.com/@coronavirusnotalone/the-secret-way-to-reopen-schools-with-batch-testing-for-coronavirus-616433cd5ba4
// https://medium.com/@coronavirusnotalone/a-secret-simple-way-to-detect-the-coronavirus-without-a-test-for-everyone-9e06afb2823a




function processWaves(startvalue,endvalue,waveindex) {
  console.log("processing " + startvalue + "start " + endvalue + "end " + waveindex +  "waveindex");
  let localTestCount=0;
  // debugger;
  if (startvalue==endvalue) {
    // the batch size is 1
    // console.log("size1");
    return 1;
  }

  //check for any true
  var someTrue= arrayOfInfection.slice(startvalue,endvalue+1).some((x)=> x==true);

  if (someTrue) {
    localTestCount++
    // console.log("some true")
    // debugger;
    var waveSize=waves[waveindex];
    var currentvalue=startvalue;
    while( currentvalue<=endvalue ) {
      localTestCount=localTestCount+processWaves(currentvalue,Math.min(currentvalue+waveSize-1),waveindex+1);
      currentvalue=currentvalue+waveSize;
    }
    return localTestCount;
  } else {
    // console.log("all negative")
    return 1; // localTestCount
  }
}

var arrayOfResults=[];
var repetitions=500;

for (let i=0; i<repetitions; i++) {
  console.log("iteration " + i );
  var arrayOfRandom = Array.from({length: initialsize}, () => Math.random());
  var arrayOfInfection = arrayOfRandom.map( (x) => (x<probability) );

  var MyResult= processWaves(0,initialsize-1,0);
  console.log("MAIN RESULT");
  console.log(MyResult);
  arrayOfResults.push(MyResult);
}
console.log("Average over repititions " + repetitions);
var Average= arrayOfResults.reduce((a,b) => a + b, 0) / arrayOfResults.length
console.log(Average)