Continuous integration should include first item

__tests__/Foo/Foo__Test.re

@@ -11,7 +11,7 @@ let makeTest = (str, item1, item2) =>
 describe("Shape", () => {
   describe("Continuous", () => {
     open Distributions.Continuous;
-    let continuous = make(shape, `Stepwise);
+    let continuous = make(shape, `Linear);
     makeTest("minX", T.minX(continuous), Some(1.0));
     makeTest("maxX", T.maxX(continuous), Some(8.0));
     makeTest(
@@ -19,32 +19,75 @@ describe("Shape", () => {
       T.pointwiseFmap(r => r *. 2.0, continuous) |> getShape |> (r => r.ys),
       [|16., 18.0, 4.0|],
     );
+    describe("xToY", () => {
+      describe("when Linear", () => {
         makeTest(
-      "xToY at 4.0",
+          "at 4.0",
           T.xToY(4., continuous),
           {continuous: 9.0, discrete: 0.0},
         );
+        // Note: This below is weird to me, I'm not sure if it's what we want really.
         makeTest(
-      "xToY at 0.0",
+          "at 0.0",
           T.xToY(0., continuous),
           {continuous: 8.0, discrete: 0.0},
         );
         makeTest(
-      "xToY at 5.0",
+          "at 5.0",
           T.xToY(5., continuous),
           {continuous: 7.25, discrete: 0.0},
         );
+        makeTest(
+          "at 10.0",
+          T.xToY(10., continuous),
+          {continuous: 2.0, discrete: 0.0},
+        );
+      });
+      describe("when Stepwise", () => {
+        let continuous = make(shape, `Stepwise);
+        makeTest(
+          "at 4.0",
+          T.xToY(4., continuous),
+          {continuous: 9.0, discrete: 0.0},
+        );
+        makeTest(
+          "at 0.0",
+          T.xToY(0., continuous),
+          {continuous: 0.0, discrete: 0.0},
+        );
+        makeTest(
+          "at 5.0",
+          T.xToY(5., continuous),
+          {continuous: 9.0, discrete: 0.0},
+        );
+        makeTest(
+          "at 10.0",
+          T.xToY(10., continuous),
+          {continuous: 2.0, discrete: 0.0},
+        );
+      });
+    });
     makeTest(
       "integral",
       T.Integral.get(~cache=None, continuous) |> getShape,
-      {xs: [|4.0, 8.0|], ys: [|25.5, 47.5|]},
+      {xs: [|1.0, 4.0, 8.0|], ys: [|0.0, 25.5, 47.5|]},
+    );
+    makeTest(
+      "integralXToY",
+      T.Integral.xToY(~cache=None, 0.0, continuous),
+      0.0,
     );
     makeTest(
       "integralXToY",
       T.Integral.xToY(~cache=None, 2.0, continuous),
-      25.5,
+      8.5,
     );
-    makeTest("integralSum", T.Integral.sum(~cache=None, continuous), 73.0);
+    makeTest(
+      "integralXToY",
+      T.Integral.xToY(~cache=None, 100.0, continuous),
+      47.5,
+    );
+    makeTest("integralSum", T.Integral.sum(~cache=None, continuous), 47.5);
   });
 
   describe("Discrete", () => {
@@ -76,6 +119,23 @@ describe("Shape", () => {
       T.xToY(5., discrete),
       {discrete: 0.0, continuous: 0.0},
     );
+    makeTest(
+      "scaleBy",
+      T.scaleBy(~scale=4.0, discrete),
+      {xs: [|1., 4., 8.|], ys: [|1.2, 2.0, 0.8|]},
+    );
+    makeTest(
+      "scaleToIntegralSum",
+      T.scaleToIntegralSum(~intendedSum=4.0, discrete),
+      {xs: [|1., 4., 8.|], ys: [|1.2, 2.0, 0.8|]},
+    );
+    makeTest(
+      "scaleToIntegralSum: back and forth",
+      discrete
+      |> T.scaleToIntegralSum(~intendedSum=4.0)
+      |> T.scaleToIntegralSum(~intendedSum=1.0),
+      discrete,
+    );
     makeTest(
       "integral",
       T.Integral.get(~cache=None, discrete),
@@ -84,6 +144,11 @@ describe("Shape", () => {
         `Stepwise,
       ),
     );
+    makeTest(
+      "integral with 1 element",
+      T.Integral.get(~cache=None, {xs: [|0.0|], ys: [|1.0|]}),
+      Distributions.Continuous.make({xs: [|0.0|], ys: [|1.0|]}, `Stepwise),
+    );
     makeTest(
       "integralXToY",
       T.Integral.xToY(~cache=None, 6.0, discrete),

src/components/charts/DistPlusPlot.re

@@ -60,6 +60,12 @@ let make = (~distPlus: DistTypes.distPlus) => {
       () => {<IntegralChart distPlus onHover={r => {setX(_ => r)}} />},
       [|distPlus|],
     );
+  // Js.log4(
+  //   "distPlus",
+  //   x,
+  //   distPlus,
+  //   distPlus |> Distributions.DistPlus.T.xToY(x),
+  // );
   <div>
     chart
     chart2
@@ -67,6 +73,12 @@ let make = (~distPlus: DistTypes.distPlus) => {
       <thead>
         <tr>
           <th className="px-4 py-2"> {"X Point" |> ReasonReact.string} </th>
+          <th className="px-4 py-2">
+            {"Discrete Value" |> ReasonReact.string}
+          </th>
+          <th className="px-4 py-2">
+            {"Continuous Value" |> ReasonReact.string}
+          </th>
           <th className="px-4 py-2">
             {"Y Integral to Point" |> ReasonReact.string}
           </th>
@@ -77,6 +89,20 @@ let make = (~distPlus: DistTypes.distPlus) => {
           <th className="px-4 py-2 border ">
             {x |> E.Float.toString |> ReasonReact.string}
           </th>
+          <th className="px-4 py-2 border ">
+            {distPlus
+             |> Distributions.DistPlus.T.xToY(x)
+             |> DistTypes.MixedPoint.toDiscreteValue
+             |> E.Float.with2DigitsPrecision
+             |> ReasonReact.string}
+          </th>
+          <th className="px-4 py-2 border ">
+            {distPlus
+             |> Distributions.DistPlus.T.xToY(x)
+             |> DistTypes.MixedPoint.toContinuousValue
+             |> E.Float.with2DigitsPrecision
+             |> ReasonReact.string}
+          </th>
           <th className="px-4 py-2 border ">
             {distPlus
              |> Distributions.DistPlus.T.Integral.xToY(~cache=None, x)

src/distributions/Distributions.re

@@ -90,8 +90,9 @@ module Continuous = {
       type t = DistTypes.continuousShape;
       type integral = DistTypes.continuousShape;
       let shapeFn = (fn, t: t) => t |> xyShape |> fn;
-      // TODO: Obviously fix this, it's terrible. Use interpolation method here.
+      // TODO: Obviously fix this, it's terrible. Use interpolation param to do appropriate interpolation.
       // TODO: Steps could be 1 value, interpolation needs at least 2.
+      // TODO: integrateWithTriangles should return (x0, 0.0) as the first item.
       let integral = (~cache, t) =>
         cache
         |> E.O.default(
@@ -103,16 +104,28 @@ module Continuous = {
            );
       //   This seems wrong, we really want the ending bit, I'd assume
       let integralSum = (~cache, t) =>
-        t |> integral(~cache) |> xyShape |> XYShape.ySum;
+        t
+        |> integral(~cache)
+        |> xyShape
+        |> XYShape.unsafeLast
+        |> (((_, y)) => y);
       let minX = shapeFn(XYShape.minX);
       let maxX = shapeFn(XYShape.maxX);
       let pointwiseFmap = (fn, t: t) =>
         t |> xyShape |> XYShape.pointwiseMap(fn) |> fromShape;
       let toShape = (t: t): DistTypes.shape => Continuous(t);
-      // TODO: When Roman's PR comes in, fix this bit. This depends on interpolation, obviously.
+      let xToY = (f, {interpolation, xyShape}: t) =>
-      let xToY = (f, t) =>
+        switch (interpolation) {
-        shapeFn(CdfLibrary.Distribution.findY(f), t)
+        | `Stepwise =>
-        |> DistTypes.MixedPoint.makeContinuous;
+          xyShape
+          |> XYShape.XtoY.stepwise(f)
+          |> E.O.default(0.0)
+          |> DistTypes.MixedPoint.makeContinuous
+        | `Linear =>
+          xyShape
+          |> XYShape.XtoY.linear(f)
+          |> DistTypes.MixedPoint.makeContinuous
+        };
       let integralXtoY = (~cache, f, t) =>
         t |> integral(~cache) |> shapeFn(CdfLibrary.Distribution.findY(f));
       let toContinuous = t => Some(t);
@@ -138,7 +151,6 @@ module Discrete = {
                Continuous.make(XYShape.accumulateYs(t), `Stepwise);
              },
            );
-      //  todo: Fix this with last element
       let integralSum = (~cache, t) => t |> XYShape.ySum;
       let minX = XYShape.minX;
       let maxX = XYShape.maxX;
@@ -150,8 +162,7 @@ module Discrete = {
       let toScaledDiscrete = t => Some(t);
 
       let xToY = (f, t) => {
-        XYShape.getBy(t, ((x, _)) => x == f)
+        XYShape.XtoY.ifAtX(f, t)
-        |> E.O.fmap(((_, y)) => y)
         |> E.O.default(0.0)
         |> DistTypes.MixedPoint.makeDiscrete;
       };

src/distributions/XYShape.re

@@ -18,8 +18,36 @@ let last = (t: t) =>
   | _ => None
   };
 
+let unsafeFirst = (t: t) => first(t) |> E.O.toExn("Unsafe operation");
+let unsafeLast = (t: t) => last(t) |> E.O.toExn("Unsafe operation");
+
 let zip = t => Belt.Array.zip(t.xs, t.ys);
 let getBy = (t: t, fn) => t |> zip |> Belt.Array.getBy(_, fn);
+
+let firstPairAtOrBeforeValue = (xValue, t: t) => {
+  let zipped = zip(t);
+  let firstIndex =
+    zipped |> Belt.Array.getIndexBy(_, ((x, y)) => x > xValue);
+  let previousIndex =
+    switch (firstIndex) {
+    | None => Some(Array.length(zipped) - 1)
+    | Some(0) => None
+    | Some(n) => Some(n - 1)
+    };
+  previousIndex |> Belt.Option.flatMap(_, Belt.Array.get(zipped));
+};
+
+module XtoY = {
+  let ifAtX = (f, t: t) =>
+    getBy(t, ((x, _)) => x == f) |> E.O.fmap(((_, y)) => y);
+
+  let stepwise = (f, t: t) =>
+    firstPairAtOrBeforeValue(f, t) |> E.O.fmap(((_, y)) => y);
+
+  // TODO: When Roman's PR comes in, fix this bit. This depends on interpolation, obviously.
+  let linear = (f, t: t) => t |> CdfLibrary.Distribution.findY(f);
+};
+
 let pointwiseMap = (fn, t: t): t => {xs: t.xs, ys: t.ys |> E.A.fmap(fn)};
 let fromArray = ((xs, ys)): t => {xs, ys};
 let fromArrays = (xs, ys): t => {xs, ys};
@@ -109,21 +137,24 @@ module Range = {
       (((lastX, lastY), (nextX, nextY)): zippedRange) =>
     (nextY -. lastY) /. (nextX -. lastX);
 
-  let inRanges = (mapper, reducer, t: t) => {
+  let mapYsBasedOnRanges = (fn, t) =>
     Belt.Array.zip(t.xs, t.ys)
     |> E.A.toRanges
     |> E.R.toOption
-    |> E.O.fmap(r => r |> Belt.Array.map(_, mapper) |> reducer);
+    |> E.O.fmap(r => r |> Belt.Array.map(_, r => (nextX(r), fn(r))));
-  };
 
-  let mapYsBasedOnRanges = fn => inRanges(r => (nextX(r), fn(r)), toT);
+  let integrateWithTriangles = z => {
-
+    let rangeItems = mapYsBasedOnRanges(rangeAreaAssumingTriangles, z);
-  let integrateWithSteps = z =>
+    (
-    mapYsBasedOnRanges(rangeAreaAssumingSteps, z) |> E.O.fmap(accumulateYs);
+      switch (rangeItems, z |> first) {
-
+      | (Some(r), Some((firstX, _))) =>
-  let integrateWithTriangles = z =>
+        Some(Belt.Array.concat([|(firstX, 0.0)|], r))
-    mapYsBasedOnRanges(rangeAreaAssumingTriangles, z)
+      | _ => None
+      }
+    )
+    |> E.O.fmap(toT)
     |> E.O.fmap(accumulateYs);
+  };
 
   let derivative = mapYsBasedOnRanges(delta_y_over_delta_x);