diff --git a/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/NumericShapeCombination2.res b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/NumericShapeCombination2.res new file mode 100644 index 00000000..10f49857 --- /dev/null +++ b/packages/squiggle-lang/src/rescript/Distributions/PointSetDist/NumericShapeCombination2.res @@ -0,0 +1,114 @@ +let emptyXYShape: PointSetTypes.xyShape = {xs: [], ys: []} +exception LogicallyInconsistent(string) + +let getApproximatePdfOfContinuousDistributionAtPoint = ( + dist: PointSetTypes.xyShape, + point: float, +): float => { + let closestFromBelowIndex = E.A.reducei(dist.xs, None, (accumulator, item, index) => + item < point ? Some(index) : accumulator + ) + let closestFromAboveIndexOption = Belt.Array.getIndexBy(dist.xs, item => item > point) + + let weightedMean = ( + point: float, + closestFromBelow: float, + closestFromAbove: float, + valueclosestFromBelow, + valueclosestFromAbove, + ): float => { + let distance = closestFromAbove -. closestFromBelow + let w1 = (point -. closestFromBelow) /. distance + let w2 = (closestFromAbove -. point) /. distance + let result = w1 *. valueclosestFromAbove +. w2 *. valueclosestFromBelow + result + } + + let result = switch (closestFromBelowIndex, closestFromAboveIndexOption) { + | (None, None) => + raise( + LogicallyInconsistent( + "Logically inconsistent option in NumericShapeCombination2.res. Possibly caused by empty distribution", + ), + ) // all are smaller, and all are larger + | (None, Some(i)) => 0.0 // none are smaller, all are larger + | (Some(i), None) => 0.0 // all are smaller, none are larger + | (Some(i), Some(j)) => weightedMean(point, dist.xs[i], dist.xs[j], dist.ys[i], dist.ys[j]) // there is a lowerBound and an upperBound. + } + + result +} + +let addContinuousContinuous = ( + s1: PointSetTypes.xyShape, + s2: PointSetTypes.xyShape, +): PointSetTypes.xyShape => { + // Assumption: xyShapes are ordered on the x coordinate. + + // Get some needed variables + let len1 = XYShape.T.length(s1) + let mins1xs = s1.xs[0] // Belt.Array.reduce(s1.xs, s1.xs[0], (a, b) => a < b ? a : b) + let maxs1xs = s1.xs[len1 - 1] // Belt.Array.reduce(s1.xs, s1.xs[0], (a, b) => a > b ? a : b) + + let len2 = XYShape.T.length(s2) + let mins2xs = s2.xs[0] // Belt.Array.reduce(s1.xs, s1.xs[0], (a, b) => a < b ? a : b) + let maxs2xs = s2.xs[len1 - 1] // Belt.Array.reduce(s1.xs, s1.xs[0], (a, b) => a > b ? a : b) + + let lowerBound = mins1xs +. mins2xs + let upperBound = maxs1xs +. maxs2xs + let numIntervals = 2 * Js.Math.max_int(len1, len2) + let epsilon = (upperBound -. lowerBound) /. Belt.Int.toFloat(numIntervals) // Js.Math.pow_float(~base=2.0, ~exp=-16.0) + + let newXs: array = Belt.Array.makeUninitializedUnsafe(numIntervals) + let newYs: array = Belt.Array.makeUninitializedUnsafe(numIntervals) + + let getApproximatePdfOfS1AtPoint = x => getApproximatePdfOfContinuousDistributionAtPoint(s1, x) + let getApproximatePdfOfS2AtPoint = x => getApproximatePdfOfContinuousDistributionAtPoint(s2, x) + let float = x => Belt.Int.toFloat(x) + // Compute the integral numerically. + for i in 0 to numIntervals - 1 { + newXs[i] = lowerBound +. float(i) *. epsilon + newYs[i] = 0.0 + for j in 0 to numIntervals - 1 { + let deltaYi = + getApproximatePdfOfS1AtPoint(lowerBound +. float(j) *. epsilon) *. + getApproximatePdfOfS2AtPoint(float(i) *. epsilon -. float(j) *. epsilon) + // lowerBound +. float(i) *. epsilon - (lowerBound +. float(j) *. epsilon) + newYs[i] = newYs[i] +. deltaYi + } + } + // This could be improved by, for instance, choosing the location of the xs strategically + // for example, such that each of them is "equidistant" in a cdf, that is, such that the + // cdf increases by constant amounts from one point to another. + {xs: newXs, ys: newYs} +} + +let combineShapesContinuousContinuous = ( + op: Operation.algebraicOperation, + s1: PointSetTypes.xyShape, + s2: PointSetTypes.xyShape, +): PointSetTypes.xyShape => { + let result = switch op { + | #Add => addContinuousContinuous(s1, s2) + | #Subtract => emptyXYShape + | #Multiply => emptyXYShape + | #Power => emptyXYShape + | #Logarithm => emptyXYShape + | #Divide => emptyXYShape + } + result +} + +// Not sure I understand how to combine continuous and discrete distribution + +let combineShapesContinuousDiscrete = ( + op: Operation.algebraicOperation, + continuousShape: PointSetTypes.xyShape, + discreteShape: PointSetTypes.xyShape, +): PointSetTypes.xyShape => emptyXYShape + +let combineShapesDiscreteContinuous = ( + op: Operation.algebraicOperation, + discreteShape: PointSetTypes.xyShape, + continuousShape: PointSetTypes.xyShape, +): PointSetTypes.xyShape => emptyXYShape