From 088a623bef7e2355d4bbfd5da8d8d2fdafdbb3eb Mon Sep 17 00:00:00 2001
From: Ozzie Gooen <ozzieagooen@gmail.com>
Date: Thu, 13 Feb 2020 12:40:04 +0000
Subject: [PATCH] Use lognormal instead of normal

---
 src/lib/FloatCdf.re   | 10 ++++++++++
 src/lib/Prop.re       |  7 ++-----
 src/models/EAFunds.re |  5 ++++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/lib/FloatCdf.re b/src/lib/FloatCdf.re
index d94c209b..f13e112b 100644
--- a/src/lib/FloatCdf.re
+++ b/src/lib/FloatCdf.re
@@ -7,4 +7,14 @@ let normal = (mean: float, std: float) =>
     }
   );
 
+let logNormal = (mean: float, std: float) => {
+  Js.Float.(
+    {
+      let nMean = toPrecisionWithPrecision(Js.Math.log10(mean), ~digits=4);
+      let nStd = toPrecisionWithPrecision(std, ~digits=2);
+      {j|lognormal($(nMean), $(nStd))|j};
+    }
+  );
+};
+
 let divide = (str1: string, str2: string) => {j|$(str1)/$(str2)|j};
\ No newline at end of file
diff --git a/src/lib/Prop.re b/src/lib/Prop.re
index ddcae4ff..57a77e54 100644
--- a/src/lib/Prop.re
+++ b/src/lib/Prop.re
@@ -18,10 +18,7 @@ module Value = {
       | Unselected => ""
       }
     | SelectSingle(r) => r
-    | FloatCdf(r) =>
-      let foo: Types.distribution =
-        CdfLibrary.Distribution.fromString(r, 100);
-      r;
+    | FloatCdf(r) => r
     | Probability(r) => (r *. 100. |> Js.Float.toFixed) ++ "%"
     | DateTime(r) => r |> MomentRe.Moment.defaultFormat
     | FloatPoint(r) => r |> Js.Float.toFixed
@@ -41,7 +38,7 @@ module Value = {
     | SelectSingle(r) => r |> ReasonReact.string
     | FloatCdf(r) =>
       let cdf: Types.distribution =
-        CdfLibrary.Distribution.fromString(r, 100);
+        CdfLibrary.Distribution.fromString(r, 1000);
       <>
         <ForetoldComponents.CdfChart__Large
           cdf={Types.toComponentsDist(cdf)}
diff --git a/src/models/EAFunds.re b/src/models/EAFunds.re
index 0d8814a3..df2659b8 100644
--- a/src/models/EAFunds.re
+++ b/src/models/EAFunds.re
@@ -78,7 +78,10 @@ module Model = {
     let yearDiff = MomentRe.diff(dateTime, currentDateTime, `days) /. 365.;
     let meanDiff = Js.Math.pow_float(~base=y.meanDiff, ~exp=yearDiff);
     let stdDevDiff = Js.Math.pow_float(~base=y.meanDiff, ~exp=yearDiff);
-    FloatCdf.normal(currentValue *. meanDiff, firstYearStdDev *. stdDevDiff);
+    FloatCdf.logNormal(
+      currentValue *. meanDiff,
+      firstYearStdDev *. stdDevDiff,
+    );
   };
 
   let rec currentValue = (group: group, output) => {