Dual access for grid origins

src/main/java/com/conveyal/analysis/results/MultiOriginAssembler.java

@@ -139,7 +139,8 @@ public MultiOriginAssembler (RegionalAnalysis regionalAnalysis, Job job, FileSto
                     // We might want to record a grid of dual accessibility values, but this will require some serious
                     // refactoring of the GridResultWriter.
                     // if (job.templateTask.dualAccessibilityThreshold > 0) { ... }
-                    throw new IllegalArgumentException("Temporal density of opportunities cannot be recorded for gridded origin points.");
+                    // throw new IllegalArgumentException("Temporal density of opportunities cannot be recorded for " +
+                    //        "gridded origin points.");
                 } else {
                     // Freeform origins.
                     // Output includes temporal density of opportunities and optionally dual accessibility.

src/main/java/com/conveyal/r5/analyst/TemporalDensityResult.java

@@ -1,6 +1,7 @@
 package com.conveyal.r5.analyst;
 
 import com.conveyal.r5.analyst.cluster.AnalysisWorkerTask;
+import com.conveyal.r5.analyst.cluster.RegionalTask;
 import com.google.common.base.Preconditions;
 
 import static com.conveyal.r5.common.Util.notNullOrEmpty;
@@ -89,6 +90,50 @@ public int[][] minutesToReachOpportunities(int n) {
         return result;
     }
 
+    /**
+     * Writes dual access travel time values (in minutes) to our standard access grid format. The value returned (for
+     * an origin) is the number of minutes required to reach a threshold number of opportunities (specified by
+     * the cutoffs and task.dualAccessibilityThreshold) in the specified destination layer at a given percentile of
+     * travel time. If the threshold cannot be reached in less than 120 minutes, returns 0.
+     * This is a temporary experimental feature, (ab)using existing features in the UI and backend so that dual access
+     * results for grid origins can be obtained without any changes to those other components of our system. It uses
+     * the supplied task.cutoffsMinutes as dual access thresholds. If a nonzero task.dualAccessibility In place of the
+     * last
+     * cutoffsMinutes value, it uses task.dualAccessibilityThreshold (which is initialized to 0, so this is safe even
+     * if a user does not supply it).
+     */
+    public int[][][] fakeDualAccess (RegionalTask task) {
+        int nPointSets = task.destinationPointSets.length;
+        int nCutoffs = task.cutoffsMinutes.length;
+        int[][][] dualAccess = new int[nPointSets][nPercentiles][nCutoffs];
+        for (int d = 0; d < nPointSets; d++) {
+            for (int p = 0; p < nPercentiles; p++) {
+                // Hack: use cutoffs as dual access thresholds
+                for (int c = 0; c < nCutoffs; c++) {
+                    int m = 0;
+                    double sum = 0;
+                    while (sum < task.cutoffsMinutes[c] && m < 120) {
+                        sum += opportunitiesPerMinute[d][p][m];
+                        m += 1;
+                    }
+                    dualAccess[d][p][c] = m;
+                }
+                // But the hack above won't allow thresholds over 120 (see validateCutoffsMinutes()); so overwrite
+                // the value for the last cutoff if a nonzero task.dualAccessibilityThreshold value is supplied.
+                if (task.dualAccessibilityThreshold != 0) {
+                    int m = 0;
+                    double sum = 0;
+                    while (sum < task.dualAccessibilityThreshold && m < 120) {
+                        sum += opportunitiesPerMinute[d][p][m];
+                        m += 1;
+                    }
+                    dualAccess[d][p][nCutoffs - 1] = m;
+                }
+            }
+        }
+        return dualAccess;
+    }
+
     public int[][] minutesToReachOpportunities() {
         return minutesToReachOpportunities(opportunityThreshold);
     }

src/main/java/com/conveyal/r5/analyst/TravelTimeReducer.java

@@ -145,7 +145,7 @@ public TravelTimeReducer (AnalysisWorkerTask task, TransportNetwork network) {
         if (task.includePathResults) {
             pathResult = new PathResult(task, network.transitLayer);
         }
-        if (task.includeTemporalDensity) {
+        if (task.includeTemporalDensity || task.hasFlag("gridDualAccess")) {
             temporalDensityResult = new TemporalDensityResult(task);
         }
 

src/main/java/com/conveyal/r5/analyst/cluster/AnalysisWorker.java

@@ -41,6 +41,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Random;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
@@ -407,6 +408,10 @@ protected void handleOneRegionalTask (RegionalTask task) throws Throwable {
 
         LOG.debug("Handling regional task {}", task.toString());
 
+        // Force dual access results for grid (remove once broker has been relaunched to support custom flags)
+        LOG.info("Forcing dual access results");
+        task.flags = Set.of("gridDualAccess");
+
         if (task.injectFault != null) {
             task.injectFault.considerShutdownOrException(task.taskId);
             if (task.injectFault.shouldDropTaskBeforeCompute(task.taskId)) {

src/main/java/com/conveyal/r5/analyst/cluster/AnalysisWorkerTask.java

@@ -323,4 +323,8 @@ public void validateCutoffsMinutes () {
         }
     }
 
+    public boolean hasFlag (String flag) {
+        return this.flags != null && this.flags.contains(flag);
+    }
+
 }

src/main/java/com/conveyal/r5/analyst/cluster/RegionalWorkResult.java

@@ -63,7 +63,13 @@ public RegionalWorkResult(OneOriginResult result, RegionalTask task) {
         this.jobId = task.jobId;
         this.taskId = task.taskId;
         this.travelTimeValues = result.travelTimes == null ? null : result.travelTimes.values;
-        this.accessibilityValues = result.accessibility == null ? null : result.accessibility.getIntValues();
+        if (result.accessibility == null) {
+            this.accessibilityValues = null;
+        } else if (task.hasFlag("gridDualAccess")) {
+            this.accessibilityValues = result.density.fakeDualAccess(task);
+        } else {
+            this.accessibilityValues = result.accessibility.getIntValues();
+        }
         this.pathResult = result.paths == null ? null : result.paths.summarizeIterations(PathResult.Stat.MINIMUM);
         this.opportunitiesPerMinute = result.density == null ? null : result.density.opportunitiesPerMinute;
         // TODO checkTravelTimeInvariants, checkAccessibilityInvariants to verify that values are monotonically increasing