Added extra multiplicative factor in logScore integrand

Value: [8e-2 to 7e-1]

migrated intregrand from `log(predicted / answer)` to `answer *
log(predicted / answer)`

packages/squiggle-lang/__tests__/Distributions/Score_test.res

@@ -0,0 +1,3 @@
+open Jest
+open Expect
+open TestHelpers

packages/squiggle-lang/__tests__/TS/Score_test.ts

@@ -0,0 +1,19 @@
+import { testRun } from "./TestHelpers";
+
+describe("KL divergence", () => {
+  test("by integral solver agrees with analytical", () => {
+    let squiggleStringKL = `prediction=normal(4, 1)
+             answer=normal(1,1)
+             logSubtraction=dotSubtract(scaleLog(answer),scaleLog(prediction))
+             klintegrand=dotMultiply(logSubtraction, answer)
+             klintegral = integralSum(klintegrand)
+             analyticalKl = log(1 / 1) + 1 ^ 2 / (2 * 1 ^ 2) + ((4 - 1) * (1 - 4) / (2 * 1 * 1)) - 1 / 2
+             klintegral - analyticalKl`;
+    let squiggleResultKL = testRun(squiggleStringKL);
+    expect(squiggleResultKL.value).toBeCloseTo(0);
+  });
+});
+
+let squiggleStringLS = `prediction=normal(4,1)
+     answer=normal(1,1)
+     logScore(prediction, answer)`;

packages/squiggle-lang/src/rescript/Distributions/PointSetDist/Continuous.res

@@ -271,7 +271,10 @@ module T = Dist({
     XYShape.Analysis.getVarianceDangerously(t, mean, Analysis.getMeanOfSquares)
 
   let logScore = (base: t, reference: t) => {
-    combinePointwise(PointSetDist_Scoring.LogScoring.logScore, base, reference)
+    E.R2.bind(
+      combinePointwise(PointSetDist_Scoring.LogScoring.multiply, reference),
+      combinePointwise(PointSetDist_Scoring.LogScoring.logScore, base, reference),
+    )
     |> E.R.fmap(shapeMap(XYShape.T.filterYValues(Js.Float.isFinite)))
     |> E.R.fmap(integralEndY)
   }

packages/squiggle-lang/src/rescript/Distributions/PointSetDist/PointSetDist_Scoring.res

@@ -4,4 +4,5 @@ module LogScoring = {
   let logScore = (a: float, b: float): result<float, Operation.Error.t> => Ok(
     Js.Math.log2(Js.Math.abs_float(a /. b)),
   )
+  let multiply = (a: float, b: float): result<float, Operation.Error.t> => Ok(a *. b)
 }