squiggle/src/core/Shape.re
2020-02-17 09:21:15 +00:00

94 lines
2.2 KiB
ReasonML

open DistributionTypes;
let _lastElement = (a: array('a)) =>
switch (Belt.Array.size(a)) {
| 0 => None
| n => Belt.Array.get(a, n)
};
module XYShape = {
type t = xyShape;
let toJs = (t: t) => {
{"xs": t.xs, "ys": t.ys};
};
let fmap = (t: t, y): t => {xs: t.xs, ys: t.ys |> E.A.fmap(y)};
let yFold = (fn, t: t) => {
E.A.fold_left(fn, 0., t.ys);
};
let ySum = yFold((a, b) => a +. b);
let fromArrays = (xs, ys): t => {xs, ys};
let transverse = (fn, p: t) => {
let (xs, ys) =
Belt.Array.zip(p.xs, p.ys)
->Belt.Array.reduce([||], (items, (x, y)) =>
switch (_lastElement(items)) {
| Some((_, yLast)) => [|(x, fn(y, yLast))|]
| None => [|(x, y)|]
}
)
|> Belt.Array.unzip;
fromArrays(xs, ys);
};
let derivative = transverse((aCurrent, aLast) => aCurrent -. aLast);
let integral = transverse((aCurrent, aLast) => aCurrent +. aLast);
};
module Continuous = {
let fromArrays = XYShape.fromArrays;
let toJs = XYShape.toJs;
let toPdf = CdfLibrary.Distribution.toPdf;
let toCdf = CdfLibrary.Distribution.toCdf;
let findX = CdfLibrary.Distribution.findX;
let findY = CdfLibrary.Distribution.findY;
};
module Discrete = {
type t = discreteShape;
let fromArrays = XYShape.fromArrays;
let toJs = XYShape.toJs;
let ySum = XYShape.ySum;
let zip = t => Belt.Array.zip(t.xs, t.ys);
let scaleYToTotal = (totalDesired, t: t): t => {
let difference = totalDesired /. ySum(t);
XYShape.fmap(t, y => y *. difference);
};
let render = (t: t) =>
Belt.Array.zip(t.xs, t.ys)
|> E.A.fmap(((x, y)) =>
<div>
{E.Float.toFixed(x)
++ "---"
++ E.Float.with3DigitsPrecision(y *. 100.)
|> ReasonReact.string}
</div>
)
|> ReasonReact.array;
let findY = (x: float, t: t) =>
switch (E.A.getBy(zip(t), ((ix, _)) => ix == x)) {
| Some((_, y)) => y
| None => 0.
};
};
module Mixed = {
let make = (~continuous, ~discrete, ~discreteProbabilityMassFraction) => {
continuous,
discrete,
discreteProbabilityMassFraction,
};
};
module DomainMixed = {
type t = {
mixedShape,
domain,
};
};