Added Truncate to sci.res

packages/squiggle-lang/src/rescript/sci.res

@@ -1,3 +1,5 @@
+//TODO: multimodal, add interface, split up a little bit, test somehow, track performance, refactor sampleSet, refactor ASTEvaluator.res.
+
 type error =
   | NeedsPointSetConversion
   | InputsNeedPointSetConversion
@@ -18,7 +20,7 @@ module OperationType = {
     | #Pointwise
   ]
 
-  type combination = [
+  type arithmeticOperation = [
     | #Add
     | #Multiply
     | #Subtract
@@ -27,8 +29,8 @@ module OperationType = {
     | #Log
   ]
 
-  let combinationToFn = (combination: combination) =>
-    switch combination {
+  let arithmeticToFn = (arithmetic: arithmeticOperation) =>
+    switch arithmetic {
     | #Add => \"+."
     | #Multiply => \"*."
     | #Subtract => \"-."
@@ -49,6 +51,7 @@ module OperationType = {
     | #normalize
     | #toPointSet
     | #toSampleSet(int)
+    | #truncate(option<float>, option<float>)
   ]
 
   type toFloatArray = [
@@ -58,7 +61,7 @@ module OperationType = {
   type t = [
     | #toFloat(toFloat)
     | #toDist(toDist)
-    | #toDistCombination(direction, combination, [#Dist(genericDist) | #Float(float)])
+    | #toDistCombination(direction, arithmeticOperation, [#Dist(genericDist) | #Float(float)])
   ]
 }
 
@@ -76,6 +79,14 @@ module T = {
     }
   }
 
+  let normalize = (t: t) => {
+    switch t {
+    | #PointSet(r) => #PointSet(PointSetDist.T.normalize(r))
+    | #Symbolic(_) => t
+    | #SampleSet(_) => t
+    }
+  }
+
   let toFloat = (toPointSet: toPointSetFn, fnName, t: genericDist): result<float, error> => {
     switch t {
     | #Symbolic(r) if Belt.Result.isOk(SymbolicDist.T.operate(fnName, r)) =>
@@ -117,10 +128,46 @@ module T = {
     }
   }
 
+  module Truncate = {
+    let trySymbolicSimplification = (leftCutoff, rightCutoff, t): option<t> =>
+      switch (leftCutoff, rightCutoff, t) {
+      | (None, None, _) => None
+      | (lc, rc, #Symbolic(#Uniform(u))) if lc < rc =>
+        Some(#Symbolic(#Uniform(SymbolicDist.Uniform.truncate(lc, rc, u))))
+      | _ => None
+      }
+
+    let run = (
+      toPointSet: toPointSetFn,
+      leftCutoff: option<float>,
+      rightCutoff: option<float>,
+      t: t,
+    ): result<t, error> => {
+      let doesNotNeedCutoff = E.O.isNone(leftCutoff) && E.O.isNone(rightCutoff)
+      if doesNotNeedCutoff {
+        Ok(t)
+      } else {
+        switch trySymbolicSimplification(leftCutoff, rightCutoff, t) {
+        | Some(r) => Ok(r)
+        | None =>
+          toPointSet(t) |> E.R.fmap(t =>
+            #PointSet(PointSetDist.T.truncate(leftCutoff, rightCutoff, t))
+          )
+        }
+      }
+    }
+  }
+
+  /* Given two random variables A and B, this returns the distribution
+   of a new variable that is the result of the operation on A and B.
+   For instance, normal(0, 1) + normal(1, 1) -> normal(1, 2).
+   In general, this is implemented via convolution. */
   module AlgebraicCombination = {
-    let tryAnalyticalSimplification = (operation: OperationType.combination, t1: t, t2: t): option<
-      result<SymbolicDistTypes.symbolicDist, string>,
-    > =>
+    let tryAnalyticalSimplification = (
+      operation: OperationType.arithmeticOperation,
+      t1: t,
+      t2: t,
+    ): option<result<SymbolicDistTypes.symbolicDist, string>> =>
       switch (operation, t1, t2) {
       | (operation, #Symbolic(d1), #Symbolic(d2)) =>
         switch SymbolicDist.T.tryAnalyticalSimplification(d1, d2, operation) {
@@ -133,7 +180,7 @@ module T = {
 
     let runConvolution = (
       toPointSet: toPointSetFn,
-      operation: OperationType.combination,
+      operation: OperationType.arithmeticOperation,
       t1: t,
       t2: t,
     ) =>
@@ -143,7 +190,7 @@ module T = {
 
     let runMonteCarlo = (
       toSampleSet: toSampleSetFn,
-      operation: OperationType.combination,
+      operation: OperationType.arithmeticOperation,
       t1: t,
       t2: t,
     ) => {
@@ -163,7 +210,7 @@ module T = {
       | _ => 1000
       }
 
-    let chooseConvolutionOrMonteCarlo = (t1: t, t2: t) =>
+    let chooseConvolutionOrMonteCarlo = (t2: t, t1: t) =>
       expectedConvolutionCost(t1) * expectedConvolutionCost(t2) > 10000
         ? #CalculateWithMonteCarlo
         : #CalculateWithConvolution
@@ -189,22 +236,23 @@ module T = {
     }
   }
 
-  let pointwiseCombination = (toPointSet: toPointSetFn, operation, t1: t, t2: t): result<
+  //TODO: Add faster pointwiseCombine fn
+  let pointwiseCombination = (toPointSet: toPointSetFn, operation, t2: t, t1: t): result<
     t,
     error,
   > => {
     E.R.merge(toPointSet(t1), toPointSet(t2))
     |> E.R.fmap(((t1, t2)) =>
-      PointSetDist.combinePointwise(OperationType.combinationToFn(operation), t1, t2)
+      PointSetDist.combinePointwise(OperationType.arithmeticToFn(operation), t1, t2)
     )
     |> E.R.fmap(r => #PointSet(r))
   }
 
   let pointwiseCombinationFloat = (
     toPointSet: toPointSetFn,
-    operation: OperationType.combination,
-    t: t,
+    operation: OperationType.arithmeticOperation,
     f: float,
+    t: t,
   ): result<t, error> => {
     switch operation {
     | #Add | #Subtract => Error(DistributionVerticalShiftIsInvalid)
@@ -259,36 +307,41 @@ module OmniRunner = {
       switch reCall(~value=r, ~fnName=#toDist(#toPointSet), ()) {
       | #Dist(#PointSet(p)) => Ok(p)
       | #Error(r) => Error(r)
-      | _ => Error(Other("Impossible error"))
+      | _ => Error(ImpossiblePath)
       }
     }
     let toSampleSet = r => {
       switch reCall(~value=r, ~fnName=#toDist(#toSampleSet(sampleCount)), ()) {
       | #Dist(#SampleSet(p)) => Ok(p)
       | #Error(r) => Error(r)
-      | _ => Error(Other("Impossible error"))
+      | _ => Error(ImpossiblePath)
       }
     }
-    switch (fnName, value) {
+    switch fnName {
     // | (#toFloat(n), v) => toFloat(toPointSet, v, n)
-    | (#toFloat(fnName), _) =>
+    | #toFloat(fnName) =>
       T.toFloat(toPointSet, fnName, value) |> E.R.fmap(r => #Float(r)) |> fromResult
-    | (#toDist(#normalize), #PointSet(r)) => #Dist(#PointSet(PointSetDist.T.normalize(r)))
-    | (#toDist(#normalize), #Symbolic(_)) => #Dist(value)
-    | (#toDist(#normalize), #SampleSet(_)) => #Dist(value)
-    | (#toDist(#toPointSet), _) =>
+    | #toDist(#normalize) => value |> T.normalize |> (r => #Dist(r))
+    | #toDist(#truncate(left, right)) =>
+      value |> T.Truncate.run(toPointSet, left, right) |> E.R.fmap(r => #Dist(r)) |> fromResult
+    | #toDist(#toPointSet) =>
       value |> T.toPointSet(xyPointLength) |> E.R.fmap(r => #Dist(#PointSet(r))) |> fromResult
-    | (#toDist(#toSampleSet(n)), _) =>
+    | #toDist(#toSampleSet(n)) =>
       value |> T.sampleN(n) |> E.R.fmap(r => #Dist(#SampleSet(r))) |> fromResult
-    | (#toDistCombination(#Algebraic, _, #Float(_)), _) => #Error(NotYetImplemented)
-    | (#toDistCombination(#Algebraic, operation, #Dist(p2)), p1) =>
-      T.AlgebraicCombination.run(toPointSet, toSampleSet, operation, p1, p2)
+    | #toDistCombination(#Algebraic, _, #Float(_)) => #Error(NotYetImplemented)
+    | #toDistCombination(#Algebraic, operation, #Dist(value2)) =>
+      value
+      |> T.AlgebraicCombination.run(toPointSet, toSampleSet, operation, value2)
       |> E.R.fmap(r => #Dist(r))
       |> fromResult
-    | (#toDistCombination(#Pointwise, operation, #Dist(p2)), p1) =>
-      T.pointwiseCombination(toPointSet, operation, p1, p2) |> E.R.fmap(r => #Dist(r)) |> fromResult
-    | (#toDistCombination(#Pointwise, operation, #Float(f)), _) =>
-      T.pointwiseCombinationFloat(toPointSet, operation, value, f)
+    | #toDistCombination(#Pointwise, operation, #Dist(value2)) =>
+      value
+      |> T.pointwiseCombination(toPointSet, operation, value2)
+      |> E.R.fmap(r => #Dist(r))
+      |> fromResult
+    | #toDistCombination(#Pointwise, operation, #Float(f)) =>
+      value
+      |> T.pointwiseCombinationFloat(toPointSet, operation, f)
       |> E.R.fmap(r => #Dist(r))
       |> fromResult
     }