consistent naming, comments, fix csv writer

src/main/java/com/conveyal/analysis/models/AnalysisRequest.java

@@ -164,11 +164,16 @@ public class AnalysisRequest {
     /**
      * Whether to include the number of opportunities reached during each minute of travel in results sent back
      * to the broker. Requires both an origin and destination pointset to be specified, and in the case of regional
-     * analyses the origins must be non-gridded. (Should be possible to make a grid as well.)
+     * analyses the origins must be non-gridded, and results will be collated to CSV.
+     * It should be possible to enable regional results for gridded origins as well.
      */
-    public boolean opportunityTemporalDensity = false;
+    public boolean includeTemporalDensity = false;
 
-    public int dualAccessibilityOpportunityThreshold = 0;
+    /**
+     * If this is set to a value above zero, report the amount of time needed to reach the given number of
+     * opportunities from this origin (known technically as "dual accessibility").
+     */
+    public int dualAccessibilityThreshold = 0;
 
 
     /**
@@ -276,8 +281,8 @@ public void populateTask (AnalysisWorkerTask task, UserPermissions userPermissio
             }
         }
 
-        task.includeTemporalDensity = opportunityTemporalDensity;
-        task.dualAccessibilityThreshold = dualAccessibilityOpportunityThreshold;
+        task.includeTemporalDensity = includeTemporalDensity;
+        task.dualAccessibilityThreshold = dualAccessibilityThreshold;
     }
 
     private EnumSet<LegMode> getEnumSetFromString (String s) {

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

@@ -5,5 +5,5 @@
  * do serve to enumerate the acceptable parameters coming over the HTTP API.
  */
 public enum CsvResultType {
-    ACCESS, TIMES, PATHS, OPPORTUNITIES
+    ACCESS, TIMES, PATHS, TDENSITY
 }

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

@@ -109,8 +109,10 @@ public MultiOriginAssembler (RegionalAnalysis regionalAnalysis, Job job, FileSto
 
             if (job.templateTask.recordAccessibility) {
                 if (job.templateTask.originPointSet != null) {
+                    // Freeform origins - create CSV regional analysis results
                     resultWriters.add(new AccessCsvResultWriter(job.templateTask, fileStorage));
                 } else {
+                    // Gridded origins - create gridded regional analysis results
                     resultWriters.add(new MultiGridResultWriter(regionalAnalysis, job.templateTask, fileStorage));
                 }
             }

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

@@ -24,7 +24,7 @@ public TemporalDensityCsvResultWriter(RegionalTask task, FileStorage fileStorage
 
     @Override
     public CsvResultType resultType () {
-        return CsvResultType.OPPORTUNITIES;
+        return CsvResultType.TDENSITY;
     }
 
     @Override
@@ -59,33 +59,32 @@ protected void checkDimension (RegionalWorkResult workResult) {
 
     @Override
     public Iterable<String[]> rowValues (RegionalWorkResult workResult) {
-        List<String> row = new ArrayList<>(125);
+        List<String[]> rows = new ArrayList<>();
         String originId = task.originPointSet.getId(workResult.taskId);
         for (int d = 0; d < task.destinationPointSetKeys.length; d++) {
-            int[][] percentilesForDestPointset = workResult.accessibilityValues[d];
+            double[][] percentilesForDestPointset = workResult.opportunitiesPerMinute[d];
             for (int p = 0; p < task.percentiles.length; p++) {
+                List<String> row = new ArrayList<>(125);
                 row.add(originId);
-                row.add(task.destinationPointSets[d].name);
+                row.add(task.destinationPointSetKeys[d]);
                 row.add(Integer.toString(p));
-                int[] densitiesPerMinute = percentilesForDestPointset[p];
+                // One density value for each of 120 minutes
+                double[] densitiesPerMinute = percentilesForDestPointset[p];
                 for (int m = 0; m < 120; m++) {
                     row.add(Double.toString(densitiesPerMinute[m]));
                 }
-                // Dual accessibility
-                {
-                    int m = 0;
-                    double sum = 0;
-                    while (sum < dualThreshold) {
-                        sum += densitiesPerMinute[m];
-                        m += 1;
-                    }
-                    row.add(Integer.toString(m >= 120 ? -1 : m));
+                // One dual accessibility value
+                int m = 0;
+                double sum = 0;
+                while (sum < dualThreshold && m < 120) {
+                    sum += densitiesPerMinute[m];
+                    m += 1;
                 }
+                row.add(Integer.toString(m >= 120 ? -1 : m));
+                rows.add(row.toArray(new String[row.size()]));
             }
         }
-        // List.of() or Arrays.asList() don't work without explicitly specifying the generic type because
-        // they interpret the String[] as varargs in the method signature.
-        return List.<String[]>of(row.toArray(new String[0]));
+        return rows;
     }
 
 }

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

@@ -27,6 +27,7 @@ public class TemporalDensityResult {
 
     private final PointSet[] destinationPointSets;
     private final int nPercentiles;
+    private final int opportunityThreshold;
 
     // Externally visible fields for accumulating results
 
@@ -44,6 +45,7 @@ public TemporalDensityResult(AnalysisWorkerTask task) {
         );
         this.destinationPointSets = task.destinationPointSets;
         this.nPercentiles = task.percentiles.length;
+        this.opportunityThreshold = task.dualAccessibilityThreshold;
         this.opportunitiesPerMinute = new double[destinationPointSets.length][nPercentiles][120];
     }
 
@@ -66,7 +68,8 @@ public void recordOneTarget (int target, int[] travelTimePercentilesSeconds) {
     /**
      * Calculate "dual" accessibility from the accumulated temporal opportunity density array.
      * @param n the threshold quantity of opportunities
-     * @return the number of minutes it takes to reach n opportunities, for each destination set and percentile of travel time.
+     * @return the minimum whole number of minutes necessary to reach n opportunities,
+     *         for each destination set and percentile of travel time.
      */
     public int[][] minutesToReachOpportunities(int n) {
         int[][] result = new int[destinationPointSets.length][nPercentiles];
@@ -86,4 +89,8 @@ public int[][] minutesToReachOpportunities(int n) {
         return result;
     }
 
+    public int[][] minutesToReachOpportunities() {
+        return minutesToReachOpportunities(opportunityThreshold);
+    }
+
 }

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

@@ -536,7 +536,6 @@ public static void addJsonToGrid (
             }
             if (oneOriginResult.density != null) {
                 jsonBlock.opportunitiesPerMinute = oneOriginResult.density.opportunitiesPerMinute;
-                LOG.info("Opportunities per minute: {}", oneOriginResult.density.opportunitiesPerMinute);
             }
         }
         LOG.debug("Travel time surface written, appending {}.", jsonBlock);