diff --git a/packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Danger.res b/packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Danger.res index 9cbb0710..6e4419a6 100644 --- a/packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Danger.res +++ b/packages/squiggle-lang/src/rescript/FunctionRegistry/Library/FR_Danger.res @@ -108,8 +108,8 @@ module Internals = { } result } - let xsLength = Js.Math.ceil((max -. min) /. increment) - let xs = Belt.Array.makeBy(xsLength + 1, i => min +. Belt_Float.fromInt(i) *. increment) + let xsLength = Js.Math.floor((max -. min) /. increment) // Note that we are loosing a bit of the tail + let xs = Belt.Array.makeBy(xsLength, i => min +. (Belt_Float.fromInt(i) +. 0.5) *. increment) // makeBy goes from 0 to (n-1): let ysOptions = Belt.Array.map(xs, x => applyFunctionAtFloatToFloatOption(x)) let okYs = E.A.R.filterOk(ysOptions) @@ -149,21 +149,48 @@ module Internals = { } result } - let xsLengthCandidate = Belt.Float.toInt(Js.Math.round(numIntervals)) - let xsLength = xsLengthCandidate > 0 ? xsLengthCandidate : 1 - let increment = (max -. min) /. Belt.Int.toFloat(xsLength) - let xs = Belt.Array.makeBy(xsLength + 1, i => min +. Belt_Float.fromInt(i) *. increment) - // makeBy goes from 0 to (n-1): - let ysOptions = Belt.Array.map(xs, x => applyFunctionAtFloatToFloatOption(x)) + // worked example in comments below, assuming min=0, max = 10 + let numTotalPoints = Belt.Float.toInt(numIntervals) + let numInnerPoints = numTotalPoints - 2 + let numOuterPoints = 2 + let totalWeight = (max -. min) + let weightForAnInnerPoint = totalWeight/.E.I.toFloat(numTotalPoints-1) + let weightForAnOuterPoint = totalWeight/.E.I.toFloat(numTotalPoints-1)/. 2.0 + let innerPointIncrement = (max -. min) /. E.I.toFloat(numTotalPoints -1) + let innerXs = Belt.Array.makeBy(numInnerPoints, i => min +. Belt_Float.fromInt(i + 1) *. innerPointIncrement) + // Note that makeBy goes from 0 to (n-1): + let ysOptions = Belt.Array.map(innerXs, x => applyFunctionAtFloatToFloatOption(x)) let okYs = E.A.R.filterOk(ysOptions) + + // Logging + // assuming min = 0, max = 10, results below: + Js.Console.log2("numTotalPoints", numTotalPoints) // 5 + Js.Console.log2("numInnerPoints", numInnerPoints) // 3 + Js.Console.log2("numOuterPoints", numOuterPoints) // always 2 + Js.Console.log2("totalWeight", totalWeight) // 10 - 0 = 10 + Js.Console.log2("weightForAnInnerPoint", weightForAnInnerPoint) // 10/4 = 2.5 + Js.Console.log2("weightForAnOuterPoint", weightForAnOuterPoint) // 10/4/2 = 1.25 + Js.Console.log2("weightForAnInnerPoint * numInnerPoints + weightForAnOuterPoint * numOuterPoints", weightForAnInnerPoint *. E.I.toFloat(numInnerPoints) +. weightForAnOuterPoint *. E.I.toFloat(numOuterPoints)) // should be 10 + Js.Console.log2("sum of weights == totalWeight", (weightForAnInnerPoint *. E.I.toFloat(numInnerPoints) +. weightForAnOuterPoint *. E.I.toFloat(numOuterPoints)) == totalWeight ) // true + Js.Console.log2("innerPointIncrement", innerPointIncrement) // (10-0)/4 = 2.5 + Js.Console.log2("innerXs", innerXs) // 2.5, 5, 7.5 + Js.Console.log2("ysOptions", ysOptions) + Js.Console.log2("okYs", okYs) + let result = switch E.A.length(ysOptions) == E.A.length(okYs) { | true => { - let numericIntermediate = okYs->E.A.reduce(0.0, (a, b) => a +. b) - let numericIntermediate2 = numericIntermediate *. increment - let resultWrapped = - numericIntermediate2->ReducerInterface_InternalExpressionValue.IEvNumber->Ok - resultWrapped + let innerPointsSum = okYs->E.A.reduce(0.0, (a, b) => a +. b) + let resultWithOuterPoints = switch(applyFunctionAtFloatToFloatOption(min), applyFunctionAtFloatToFloatOption(max)){ + | (Ok(yMin), Ok(yMax)) => { + let result = ((yMin +. yMax)*.weightForAnOuterPoint +. innerPointsSum*.weightForAnInnerPoint) + let wrappedResult = result -> ReducerInterface_InternalExpressionValue.IEvNumber -> Ok + wrappedResult + } + | (Error(b), _) => Error(b) + | (_, Error(b)) => Error(b) } + resultWithOuterPoints + } | false => Error("Integration error in Danger.integrate") } result