core(metrics): update lantern coefficients

GoogleChrome · May 4, 2018 · 5ab54e3 · 5ab54e3
1 parent aad3aa6
commit 5ab54e3
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Showing 5 changed files with 16 additions and 13 deletions.
diff --git a/lighthouse-core/gather/computed/metrics/lantern-first-contentful-paint.js b/lighthouse-core/gather/computed/metrics/lantern-first-contentful-paint.js
@@ -20,9 +20,9 @@ class FirstContentfulPaint extends MetricArtifact {
    */
   get COEFFICIENTS() {
     return {
-      intercept: 1440,
-      optimistic: -1.75,
-      pessimistic: 2.73,
+      intercept: 600,
+      optimistic: .6,
+      pessimistic: .5,
     };
   }
 

diff --git a/lighthouse-core/gather/computed/metrics/lantern-first-meaningful-paint.js b/lighthouse-core/gather/computed/metrics/lantern-first-meaningful-paint.js
@@ -20,9 +20,9 @@ class FirstMeaningfulPaint extends MetricArtifact {
    */
   get COEFFICIENTS() {
     return {
-      intercept: 1532,
-      optimistic: -0.3,
-      pessimistic: 1.33,
+      intercept: 900,
+      optimistic: .45,
+      pessimistic: .6,
     };
   }
 

diff --git a/lighthouse-core/gather/computed/metrics/lantern-interactive.js b/lighthouse-core/gather/computed/metrics/lantern-interactive.js
@@ -24,9 +24,9 @@ class Interactive extends MetricArtifact {
    */
   get COEFFICIENTS() {
     return {
-      intercept: 1582,
-      optimistic: 0.97,
-      pessimistic: 0.49,
+      intercept: 1600,
+      optimistic: .6,
+      pessimistic: .45,
     };
   }
 

diff --git a/lighthouse-core/gather/computed/metrics/lantern-metric.js b/lighthouse-core/gather/computed/metrics/lantern-metric.js
@@ -82,7 +82,7 @@ class LanternMetricArtifact extends ComputedArtifact {
     const optimisticGraph = this.getOptimisticGraph(graph, traceOfTab);
     const pessimisticGraph = this.getPessimisticGraph(graph, traceOfTab);
 
-    const optimisticSimulation = simulator.simulate(optimisticGraph);
+    const optimisticSimulation = simulator.simulate(optimisticGraph, {flexibleOrdering: true});
     const pessimisticSimulation = simulator.simulate(pessimisticGraph);
 
     const optimisticEstimate = this.getEstimateFromSimulation(

diff --git a/lighthouse-core/gather/computed/metrics/lantern-speed-index.js b/lighthouse-core/gather/computed/metrics/lantern-speed-index.js
@@ -19,9 +19,12 @@ class SpeedIndex extends MetricArtifact {
    */
   get COEFFICIENTS() {
     return {
-      intercept: 200,
-      optimistic: 1.16,
-      pessimistic: 0.57,
+      // Negative intercept is OK because estimate is Math.max(FCP, Speed Index) and
+      // the optimistic estimate is based on the real observed speed index rather than a real
+      // lantern graph.
+      intercept: -250,
+      optimistic: 1.4,
+      pessimistic: 0.65,
     };
   }