From 32a881d06a7785537c577d3dea92c8759050b48b Mon Sep 17 00:00:00 2001
From: Quinn Dougherty <quinnd@riseup.net>
Date: Thu, 5 May 2022 10:38:33 -0400
Subject: [PATCH] Call Jstat for mean instead of calculate it

Value: [1e-8 to 1e-4]
---
 .../__tests__/Distributions/Dotwise_test.res  | 21 ++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/packages/squiggle-lang/__tests__/Distributions/Dotwise_test.res b/packages/squiggle-lang/__tests__/Distributions/Dotwise_test.res
index 9a77d3e5..7725aa54 100644
--- a/packages/squiggle-lang/__tests__/Distributions/Dotwise_test.res
+++ b/packages/squiggle-lang/__tests__/Distributions/Dotwise_test.res
@@ -16,12 +16,20 @@ describe("dotSubtract", () => {
       mkExponential(rate),
     )
     let meanResult = E.R2.bind(DistributionOperation.Constructors.mean(~env), dotDifference)
-    let meanAnalytical = mean -. 1.0 /. rate
+    let meanAnalytical =
+      mean -.
+      SymbolicDist.Exponential.mean({rate: rate})->E.R2.toExn(
+        "On trusted input this should never happen",
+      )
     switch meanResult {
     | Ok(meanValue) => meanValue->expect->toBeCloseTo(meanAnalytical)
     | Error(_) => raise(MeanFailed)
     }
   })
+  /*
+    It seems like this test should work, and it's plausible that
+    there's some bug in `pointwiseSubtract`
+ */
   Skip.test("mean of normal minus exponential (property)", () => {
     assert_(
       property2(float_(), floatRange(1e-5, 1e5), (mean, rate) => {
@@ -33,12 +41,11 @@ describe("dotSubtract", () => {
         )
         let meanResult = E.R2.bind(DistributionOperation.Constructors.mean(~env), dotDifference)
         // according to algebra or random variables,
-        let meanAnalytical = mean -. 1.0 /. rate
-        Js.Console.log3(
-          mean,
-          rate,
-          E.R.fmap(x => abs_float(x -. meanAnalytical) /. abs_float(meanAnalytical), meanResult),
-        )
+        let meanAnalytical =
+          mean -.
+          SymbolicDist.Exponential.mean({rate: rate})->E.R2.toExn(
+            "On trusted input this should never happen",
+          )
         switch meanResult {
         | Ok(meanValue) => abs_float(meanValue -. meanAnalytical) /. abs_float(meanValue) < 1e-2 // 1% relative error
         | Error(err) => err === DistributionTypes.OperationError(DivisionByZeroError)