fix(nlu): force coherent nlu native values (resolve #971) (#975)

botpress · Oct 3, 2018 · 991d9fb · 991d9fb
1 parent e74c0d8
commit 991d9fb
Showing 1 changed file with 20 additions and 18 deletions.
diff --git a/packages/functionals/botpress-nlu/src/providers/native.js b/packages/functionals/botpress-nlu/src/providers/native.js
@@ -144,24 +144,26 @@ export default class NativeProvider extends Provider {
 
     let allScores = zscore(classifications.map(c => parseFloat(c.value)))
 
-    const SIGMOID_ADJUSTMENT = -3.5
-    const sigmoid = t => 1 / (1 + Math.pow(Math.E, -(t + SIGMOID_ADJUSTMENT)))
-
-    allScores = allScores
-      .map((s, i) => {
-        const delta = Math.abs(s - allScores[i + 1] / s)
-        if (delta >= threshold) {
-          return s
-        }
-
-        return (
-          s -
-          Math.max(0, allScores[i + 1] || 0) * 0.5 -
-          Math.max(0, allScores[i + 2] || 0) * 0.75 -
-          Math.max(0, allScores[i + 3] || 0)
-        )
-      })
-      .map(sigmoid)
+    allScores = allScores.map((s, i) => {
+      const delta = Math.abs(s - allScores[i + 1] / s)
+      if (delta >= threshold) {
+        return s
+      }
+
+      const res =
+        s -
+        Math.max(0, allScores[i + 1] || 0) * 0.5 -
+        Math.max(0, allScores[i + 2] || 0) * 0.75 -
+        Math.max(0, allScores[i + 3] || 0)
+
+      if (res < 0) {
+        return 0
+      } else if (res > 1) {
+        return 1
+      } else {
+        return res
+      }
+    })
 
     const intents = _.orderBy(
       classifications.map((c, i) => ({