website: dynamic metrics update

1 files changed, 98 insertions, 0 deletions

diff --git a/misc/dynmet-search.js b/misc/dynmet-search.js
new file mode 100644
index 000000000..33189b8ea
--- /dev/null
+++ b/misc/dynmet-search.js
@@ -0,0 +1,98 @@
+//
+// Program that searches for optimal a,b,c values for dynamic metrics.
+//
+// Provide ideal tracking values for font sizes in idealTracking and start
+// this program. It will run forever and print to stdout when it finds
+// better a,b,c values that brings you closer to the ideal values.
+//
+// These are the initial a,b,c values. (Update if you find better values.)
+let a = -0.02, b = 0.0755, c = -0.1021 // 0.00092
+//
+// These are the ideal tracking values.
+let idealTracking = {
+  // 6:   0.05,
+  // 7:   0.04,
+  // 8:   0.03,
+  9:   0.01,
+  // 10:  0.015,
+  11:  0.005,
+  12:  0.0025,
+  13:  0,
+  // 14:  0,
+  // 15: -0.002,
+  16: -0.005,
+  // 17: -0.008,
+  18: -0.01,
+  // 20: -0.014,
+  // 24: -0.016,
+  // 30: -0.019,
+  40: -0.022,
+}
+
+
+let idealTrackingList = Object.keys(idealTracking).map(fontSize =>
+  [fontSize, idealTracking[fontSize]]
+)
+
+function sample(a, b, c) {
+  let idealDist = 0.0
+  for (let [fontSize, idealTracking] of idealTrackingList) {
+
+    let tracking = a + b * Math.pow(Math.E, c * fontSize)
+
+    let dist = Math.abs(tracking - idealTracking)
+
+    idealDist += dist
+    // console.log(`${fontSize} d=${tracking - idealTracking} d'=${dist}`)
+  }
+  // console.log(`idealDist=${idealDist}`)
+  return idealDist / idealTrackingList.length
+}
+
+const prec = 4  // precision
+let bestConstants = { a, b, c }
+let isneg = {
+  a: a < 0,
+  b: b < 0,
+  c: c < 0,
+}
+let bestDistance = sample(a, b, c)
+
+console.log(
+  '------------------------------------------------------------------\n' +
+  `| Started at ${(new Date()).toLocaleString()} with initial values:\n` +
+  `|   a = ${bestConstants.a}, b = ${bestConstants.b},` +
+  ` c = ${bestConstants.c} // D ${bestDistance.toFixed(5)}\n` +
+  `| Ctrl-C to end.\n` +
+  '------------------------------------------------------------------'
+)
+
+function logNewBest() {
+  console.log(
+    `new best: a = ${a.toFixed(prec)}, b = ${b.toFixed(prec)}, c = ${c.toFixed(prec)} // D ${bestDistance.toFixed(5)}`
+  )
+}
+
+while (true) {
+  // a = parseFloat((bestConstants.a * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+  // b = parseFloat((bestConstants.b * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+  // c = parseFloat((bestConstants.c * ((Math.random() * 2.0) - 1.0)).toFixed(prec))
+
+  let a2 = bestConstants.a * ((Math.random() * 2.0) - 1.0)
+  let b2 = bestConstants.b * ((Math.random() * 2.0) - 1.0)
+  let c2 = bestConstants.c * ((Math.random() * 2.0) - 1.0)
+
+  if (isneg.a) { if (a2 > 0) { a2 = a } } else if (a2 < 0) { a2 = a }
+  if (isneg.b) { if (b2 > 0) { b2 = b } } else if (b2 < 0) { b2 = b }
+  if (isneg.c) { if (c2 > 0) { c2 = c } } else if (c2 < 0) { c2 = c }
+
+  a = a2
+  b = b2
+  c = c2
+
+  let dist = sample(a, b, c)
+  if (dist < bestDistance) {
+    bestDistance = dist
+    logNewBest()
+  }
+}