Use LoopAlgorithm's experiments, and add Guard + Runway

Loop.xcodeproj/project.pbxproj

@@ -597,9 +597,7 @@
 		CB1AF8155B1761A30ACA5591 /* Loop/Resources/Sounds/synth.caf in Resources */ = {isa = PBXBuildFile; fileRef = 83081FFB0497A4596F597830 /* Loop/Resources/Sounds/synth.caf */; };
 		D6E28676C2C7751C77C7F2FB /* Loop/Resources/Sounds/spring.caf in Resources */ = {isa = PBXBuildFile; fileRef = 9471E156FC10D6D0FF219C77 /* Loop/Resources/Sounds/spring.caf */; };
 		DD3DBD292A33AFE9000F8B5B /* IntegralRetrospectiveCorrectionSelectionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = DD3DBD282A33AFE9000F8B5B /* IntegralRetrospectiveCorrectionSelectionView.swift */; };
-		DDC389F62A2B61750066E2E8 /* ApplicationFactorStrategy.swift in Sources */ = {isa = PBXBuildFile; fileRef = DDC389F52A2B61750066E2E8 /* ApplicationFactorStrategy.swift */; };
-		DDC389F82A2B620B0066E2E8 /* GlucoseBasedApplicationFactorStrategy.swift in Sources */ = {isa = PBXBuildFile; fileRef = DDC389F72A2B620B0066E2E8 /* GlucoseBasedApplicationFactorStrategy.swift */; };
-		DDC389FA2A2B62470066E2E8 /* ConstantApplicationFactorStrategy.swift in Sources */ = {isa = PBXBuildFile; fileRef = DDC389F92A2B62470066E2E8 /* ConstantApplicationFactorStrategy.swift */; };
+		A1B2C3D42E8F000100000002 /* GuardAndRunwaySelectionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B2C3D42E8F000100000001 /* GuardAndRunwaySelectionView.swift */; };
 		DDC389FC2A2BC6670066E2E8 /* SettingsView+algorithmExperimentsSection.swift in Sources */ = {isa = PBXBuildFile; fileRef = DDC389FB2A2BC6670066E2E8 /* SettingsView+algorithmExperimentsSection.swift */; };
 		DDC389FE2A2C4C830066E2E8 /* GlucoseBasedApplicationFactorSelectionView.swift in Sources */ = {isa = PBXBuildFile; fileRef = DDC389FD2A2C4C830066E2E8 /* GlucoseBasedApplicationFactorSelectionView.swift */; };
 		DE965737FE2DAE9FE692769E /* Loop/Resources/Sounds/alarm.caf in Resources */ = {isa = PBXBuildFile; fileRef = 0FC34B523FE5A50C920506D5 /* Loop/Resources/Sounds/alarm.caf */; };
@@ -1408,9 +1406,7 @@
 		C9SCENED0000000000000002 /* SceneDelegate.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SceneDelegate.swift; sourceTree = "<group>"; };
 		CE102E23D8C1C1291EF66387 /* PluginPickerView.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = PluginPickerView.swift; sourceTree = "<group>"; };
 		DD3DBD282A33AFE9000F8B5B /* IntegralRetrospectiveCorrectionSelectionView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IntegralRetrospectiveCorrectionSelectionView.swift; sourceTree = "<group>"; };
-		DDC389F52A2B61750066E2E8 /* ApplicationFactorStrategy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ApplicationFactorStrategy.swift; sourceTree = "<group>"; };
-		DDC389F72A2B620B0066E2E8 /* GlucoseBasedApplicationFactorStrategy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GlucoseBasedApplicationFactorStrategy.swift; sourceTree = "<group>"; };
-		DDC389F92A2B62470066E2E8 /* ConstantApplicationFactorStrategy.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConstantApplicationFactorStrategy.swift; sourceTree = "<group>"; };
+		A1B2C3D42E8F000100000001 /* GuardAndRunwaySelectionView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GuardAndRunwaySelectionView.swift; sourceTree = "<group>"; };
 		DDC389FB2A2BC6670066E2E8 /* SettingsView+algorithmExperimentsSection.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "SettingsView+algorithmExperimentsSection.swift"; sourceTree = "<group>"; };
 		DDC389FD2A2C4C830066E2E8 /* GlucoseBasedApplicationFactorSelectionView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GlucoseBasedApplicationFactorSelectionView.swift; sourceTree = "<group>"; };
 		E4854073AAE5C2CB97167F63 /* HealthAccessView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HealthAccessView.swift; sourceTree = "<group>"; };
@@ -1707,14 +1703,11 @@
 		43757D131C06F26C00910CB9 /* Models */ = {
 			isa = PBXGroup;
 			children = (
-				DDC389F52A2B61750066E2E8 /* ApplicationFactorStrategy.swift */,
 				FEEDF0000000000000000000 /* GlucoseStatistics.swift */,
 				A9FB75F0252BE320004C7D3F /* BolusDosingDecision.swift */,
 				8378B7D1F532A5F47CEBB6AE /* CarbEntryChange.swift */,
-				DDC389F92A2B62470066E2E8 /* ConstantApplicationFactorStrategy.swift */,
 				C1EF747128D6A44A00C8C083 /* CrashRecoveryManager.swift */,
 				1455ACB12C667BEE004F44F2 /* Deeplink.swift */,
-				DDC389F72A2B620B0066E2E8 /* GlucoseBasedApplicationFactorStrategy.swift */,
 				B40D07C6251A89D500C1C6D7 /* GlucoseDisplay.swift */,
 				43C2FAE01EB656A500364AFF /* GlucoseEffectVelocity.swift */,
 				C1C660D0252E4DD5009B5C32 /* LoopConstants.swift */,
@@ -2069,6 +2062,7 @@
 				C1AF062229426300002C1B19 /* ManualGlucoseEntryRow.swift */,
 				DDC389FD2A2C4C830066E2E8 /* GlucoseBasedApplicationFactorSelectionView.swift */,
 				DD3DBD282A33AFE9000F8B5B /* IntegralRetrospectiveCorrectionSelectionView.swift */,
+				A1B2C3D42E8F000100000001 /* GuardAndRunwaySelectionView.swift */,
 				84DEB10C2C18FABA00170734 /* IOSFocusModesView.swift */,
 				84D1F1A62D09053A00CB271F /* StatusTableView.swift */,
 				B429CAB22E97C7F300FA988E /* LoopStatusModalView.swift */,
@@ -3495,7 +3489,6 @@
 				1D49795824E7289700948F05 /* ServicesViewModel.swift in Sources */,
 				1D4A3E2D2478628500FD601B /* StoredAlert+CoreDataClass.swift in Sources */,
 				C1B80D632AF97D7200AB7705 /* LoopDataManager+CarbAbsorption.swift in Sources */,
-				DDC389FA2A2B62470066E2E8 /* ConstantApplicationFactorStrategy.swift in Sources */,
 				C191D2A125B3ACAA00C26C0B /* DosingStrategySelectionView.swift in Sources */,
 				A977A2F424ACFECF0059C207 /* CriticalEventLogExportManager.swift in Sources */,
 				89CA2B32226C18B8004D9350 /* TestingScenariosTableViewController.swift in Sources */,
@@ -3532,6 +3525,7 @@
 				1DDE273D24AEA4B000796622 /* SettingsViewModel.swift in Sources */,
 				FEEDB0000000000000000001 /* StatisticsViewModel.swift in Sources */,
 				DD3DBD292A33AFE9000F8B5B /* IntegralRetrospectiveCorrectionSelectionView.swift in Sources */,
+				A1B2C3D42E8F000100000002 /* GuardAndRunwaySelectionView.swift in Sources */,
 				842E40A72F22F7E2000CCCE0 /* TintedContent.swift in Sources */,
 				842E40A92F22F7E2000CCCE0 /* EstimatedReadTime.swift in Sources */,
 				842E40AA2F22F7E2000CCCE0 /* PresetsTrainingView.swift in Sources */,
@@ -3547,7 +3541,6 @@
 				1DB619AC270BAD3D006C9D07 /* VersionUpdateViewModel.swift in Sources */,
 				A9C62D882331703100535612 /* Service.swift in Sources */,
 				89CAB36324C8FE96009EE3CE /* PredictedGlucoseChartView.swift in Sources */,
-				DDC389F82A2B620B0066E2E8 /* GlucoseBasedApplicationFactorStrategy.swift in Sources */,
 				847F23432E4543140035C864 /* ActivePresetBanner.swift in Sources */,
 				84BC5BDF2E1C4A7300432000 /* InsulinDeliveryEventDetailsView.swift in Sources */,
 				4F6663941E905FD2009E74FC /* ChartColorPalette+Loop.swift in Sources */,
@@ -3632,7 +3625,6 @@
 				A97F250825E056D500F0EE19 /* OnboardingManager.swift in Sources */,
 				438D42F91D7C88BC003244B0 /* PredictionInputEffect.swift in Sources */,
 				892A5D692230C41D008961AB /* RangeReplaceableCollection.swift in Sources */,
-				DDC389F62A2B61750066E2E8 /* ApplicationFactorStrategy.swift in Sources */,
 				FEEDB0000000000000000000 /* GlucoseStatistics.swift in Sources */,
 				4F70C2101DE8FAC5006380B7 /* ExtensionDataManager.swift in Sources */,
 				1455ACB22C667BEE004F44F2 /* Deeplink.swift in Sources */,

Loop/Managers/LoopDataManager.swift

@@ -166,6 +166,8 @@ final class LoopDataManager: ObservableObject {
 
     private var lastManualBolusRecommendation: ManualBolusRecommendation?
 
+    private var volatilityBaseline: (value: Double?, date: Date)?
+
     private(set) var dosingStrategySelectionEnabled: Bool
 
     var usePositiveMomentumAndRCForManualBoluses: Bool
@@ -536,23 +538,8 @@ final class LoopDataManager: ObservableObject {
         }
 
 
-        // Create dosing strategy based on user setting
-        let applicationFactorStrategy: ApplicationFactorStrategy = UserDefaults.standard.glucoseBasedApplicationFactorEnabled
-            ? GlucoseBasedApplicationFactorStrategy()
-            : ConstantApplicationFactorStrategy()
-
-        let correctionRange = target.closestPrior(to: baseTime)?.value
-
-        let effectiveBolusApplicationFactor: Double?
-
-        if let latestGlucose = glucose.last {
-            effectiveBolusApplicationFactor = applicationFactorStrategy.calculateDosingFactor(
-                for: latestGlucose.quantity,
-                correctionRange: correctionRange!
-            )
-        } else {
-            effectiveBolusApplicationFactor = nil
-        }
+        let experiments = enabledAlgorithmExperiments
+        let volatilityBaseline = experiments.contains(.guardAndRunway) ? await currentVolatilityBaseline(at: baseTime) : nil
 
         return StoredDataAlgorithmInput(
             glucoseHistory: glucose,
@@ -566,12 +553,28 @@ final class LoopDataManager: ObservableObject {
             suspendThreshold: suspendThreshold,
             maxBolus: maxBolus,
             maxBasalRate: maxBasalRate,
-            useIntegralRetrospectiveCorrection: UserDefaults.standard.integralRetrospectiveCorrectionEnabled,
+            useIntegralRetrospectiveCorrection: false,
             includePositiveVelocityAndRC: true,
             carbAbsorptionModel: carbAbsorptionModel,
             recommendationInsulinModel: recommendationInsulinModel,
             recommendationType: .manualBolus,
-            automaticBolusApplicationFactor: effectiveBolusApplicationFactor)
+            automaticBolusApplicationFactor: nil,
+            experiments: experiments,
+            volatilityBaseline: volatilityBaseline)
+    }
+
+    private var enabledAlgorithmExperiments: Set<ExperimentOption> {
+        var experiments: Set<ExperimentOption> = []
+        if UserDefaults.standard.integralRetrospectiveCorrectionEnabled {
+            experiments.insert(.integralRetrospectiveCorrection)
+        }
+        if UserDefaults.standard.glucoseBasedApplicationFactorEnabled {
+            experiments.insert(.glucoseBasedApplicationFactor)
+        }
+        if UserDefaults.standard.guardAndRunwayEnabled {
+            experiments.insert(.guardAndRunway)
+        }
+        return experiments
     }
 
     func loopingReEnabled() async {
@@ -1053,14 +1056,31 @@ extension LoopDataManager {
 
     /// Glucose based partial application only affects automatic boluses, so it is in effect only with that strategy
     private func algorithmExperiments(for dosingStrategy: AutomaticDosingStrategy) -> [AlgorithmExperiment] {
-        var experiments: [AlgorithmExperiment] = []
-        if UserDefaults.standard.integralRetrospectiveCorrectionEnabled {
-            experiments.append(AlgorithmExperiment(identifier: "integralRetrospectiveCorrection"))
+        enabledAlgorithmExperiments
+            .filter { $0 != .glucoseBasedApplicationFactor || dosingStrategy == .automaticBolus }
+            .sorted { $0.rawValue < $1.rawValue }
+            .map { experiment in
+                let parameters: JSONValue? = experiment == .guardAndRunway
+                    ? volatilityBaseline?.value.map { .object(["volatilityBaseline": .number($0)]) }
+                    : nil
+                return AlgorithmExperiment(identifier: experiment.rawValue, parameters: parameters)
+            }
+    }
+
+    /// The median σ5 over the last four weeks, for guard + runway's volatility band. Nil until there is a day of glucose.
+    private func currentVolatilityBaseline(at date: Date) async -> Double? {
+        if let volatilityBaseline, abs(date.timeIntervalSince(volatilityBaseline.date)) < (volatilityBaseline.value == nil ? .hours(1) : .days(1)) {
+            return volatilityBaseline.value
         }
-        if UserDefaults.standard.glucoseBasedApplicationFactorEnabled && dosingStrategy == .automaticBolus {
-            experiments.append(AlgorithmExperiment(identifier: "glucoseBasedApplicationFactor"))
+        do {
+            let glucose = try await glucoseStore.getGlucoseSamples(start: date.addingTimeInterval(.days(-28)), end: date)
+            let baseline = GlucoseVolatility.baseline(glucose)
+            volatilityBaseline = (baseline, date)
+            return baseline
+        } catch {
+            logger.error("Error fetching glucose for volatility baseline: %{public}@", error.localizedDescription)
+            return volatilityBaseline?.value
         }
-        return experiments
     }
 
     func storeManualBolusDosingDecision(_ bolusDosingDecision: BolusDosingDecision, withDate date: Date) async {
@@ -1304,7 +1324,8 @@ extension StoredDataAlgorithmInput {
             algorithmEffectsOptions: effectsOptions,
             useIntegralRetrospectiveCorrection: self.useIntegralRetrospectiveCorrection,
             useMidAbsorptionISF: true,
-            carbAbsorptionModel: self.carbAbsorptionModel.model
+            carbAbsorptionModel: self.carbAbsorptionModel.model,
+            experiments: experiments
         )
         return prediction.glucose
     }
@@ -1786,8 +1807,8 @@ extension LoopDataManager: DiagnosticReportGenerator {
             "insulinOnBoard: \(String(describing: algoOutput?.activeInsulin))",
             "error: \(String(describing: loopError))",
             "overrideInUserDefaults: \(String(describing: UserDefaults.appGroup?.intentExtensionOverrideToSet))",
-            "glucoseBasedApplicationFactorEnabled: \(UserDefaults.standard.glucoseBasedApplicationFactorEnabled)",
-            "integralRetrospectiveCorrectionEanbled: \(String(describing: algoInput?.useIntegralRetrospectiveCorrection))",
+            "algorithmExperiments: \(algoInput.map { $0.experiments.map(\.rawValue).sorted() } ?? [])",
+            "volatilityBaseline: \(String(describing: algoInput?.volatilityBaseline))",
             ""
             ]
         return entries.joined(separator: "\n")

Loop/Models/StoredDataAlgorithmInput.swift

@@ -56,4 +56,8 @@ struct StoredDataAlgorithmInput: AlgorithmInput {
     var maxActiveInsulinMultiplier: Double? = nil
 
     var gradualTransitionsThreshold: Double? = nil
+
+    var experiments: Set<ExperimentOption> = []
+
+    var volatilityBaseline: Double? = nil
 }

Loop/Views/GuardAndRunwaySelectionView.swift

@@ -0,0 +1,39 @@
+//
+//  GuardAndRunwaySelectionView.swift
+//  Loop
+//
+//  Copyright © 2026 LoopKit Authors. All rights reserved.
+//
+
+import SwiftUI
+
+public struct GuardAndRunwaySelectionView: View {
+    @Binding var isGuardAndRunwayEnabled: Bool
+
+    public var body: some View {
+        ScrollView {
+            VStack(spacing: 10) {
+                Text(NSLocalizedString("Guard + Runway", comment: "Title for guard and runway experiment description"))
+                    .font(.headline)
+                    .padding(.bottom, 20)
+
+                Divider()
+
+                Text(NSLocalizedString("Guard + Runway pairs a guard against lows with a little more automatic correction when there is room for it.\n\nAfter a low: for 12 hours after a reading below 70 mg/dL (3.9 mmol/L), while glucose is below 180 mg/dL (10 mmol/L), rises count less toward retrospective correction, so the rebound after treating a low is not taken as a lasting need for more insulin.\n\nVolatility: with no carbs on board, the first two hours of the forecast are lowered according to how much glucose has been varying recently, so Loop is more cautious when glucose is unsettled.\n\nRunway: at 150 mg/dL (8.3 mmol/L) or above with no carbs on board, Loop gives some extra automatic insulin when glucose is calm enough that suspending basal could still take it back before reaching your glucose safety limit.\n\nYour correction range, manual bolus recommendations and glucose safety limit are unchanged. This experiment has been evaluated in simulation and in replays of real data, not yet by people using it.", comment: "Description of Guard + Runway experiment."))
+                    .foregroundColor(.secondary)
+                Divider()
+
+                Toggle(NSLocalizedString("Enable Guard + Runway", comment: "Title for Guard + Runway toggle"), isOn: $isGuardAndRunwayEnabled)
+                    .padding(.top, 20)
+            }
+            .padding()
+        }
+        .navigationBarTitleDisplayMode(.inline)
+    }
+}
+
+struct GuardAndRunwaySelectionView_Previews: PreviewProvider {
+    static var previews: some View {
+        GuardAndRunwaySelectionView(isGuardAndRunwayEnabled: .constant(true))
+    }
+}