tf4pi.html

  
 <html>
<body>
<script src=tf.min.js></script>
<script>
//
// tf4pi.html
// Neil Gershenfeld 11/18/18
// Ann Yuan 12/4/18
// TensorFlow.js pi calculation benchmark
// pi = 3.14159265358979323846
//

const points = 1e10;
const a = tf.scalar(0.5)
const b = tf.scalar(0.75)
const c = tf.scalar(0.25)

const indicesPerTexel = 1000;
const outputSize = points / indicesPerTexel;

const divMulIndexSubProgram = {
  variableNames: ['X', 'Y', 'Z'],
  outputShape: [outputSize],
  userCode: `
    float compute(float i) {
      return 0.5 / ((i - 0.75) * (i - 0.25));
    }

    void main() {
      float i = float(getOutputCoords());
      float sum = 0.;
      for(int index=0; index<${indicesPerTexel}; index++) {
        sum += compute(float(i * ${indicesPerTexel}. + float(index)));
      }
      setOutput(sum);
    }
  `
}

function divMulIndexSub(x, y, z) {
  return tf.ENV.backend.compileAndRun(divMulIndexSubProgram, [x, y, z]);
}

function f() {
  const product = divMulIndexSub(b, c, a);

  return tf.sum(product).dataSync();
}

// Warmup
f();

const tstart = performance.now() / 1000
const sum = f();
const tend = performance.now() / 1000
const mflops = outputSize * 5.0 * indicesPerTexel * 1e-6 / (tend - tstart);
document.write('pi: ' + sum.toString())
document.write('<br>')
document.write('time: ' + (tend - tstart) + 's')
document.write('<br>')
document.write('estimated MFlops: ' + mflops)

</script>