🔧 Pre-compute trip chains.

frontend/package.json

@@ -51,6 +51,7 @@
     "i18next-browser-languagedetector": "^7.2.0",
     "i18next-http-backend": "^2.4.2",
     "json5": "^2.2.3",
+    "object-hash": "^3.0.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-i18next": "^13.5.0",
@@ -74,6 +75,7 @@
     "@testing-library/user-event": "^14.5.1",
     "@types/country-flag-icons": "^1.2.2",
     "@types/node-fetch": "^2.6.9",
+    "@types/object-hash": "^3.0.6",
     "@types/react": "^18.2.45",
     "@types/react-dom": "^18.2.17",
     "@types/react-lazyload": "^3.2.3",

frontend/src/data_sockets/PandemosContext.tsx

@@ -1,11 +1,12 @@
 // SPDX-FileCopyrightText: 2024 German Aerospace Center (DLR)
 // SPDX-License-Identifier: Apache-2.0
 
-import React, {createContext, useEffect, useState} from 'react';
+import React, {createContext, useCallback, useEffect, useState} from 'react';
 import crossfilter, {Crossfilter} from 'crossfilter2';
 import agentList from '../../assets/pandemos/agents_lookup.json?url';
 import locationList from '../../assets/pandemos/locations_lookup.json?url';
 import trajectories from '../../assets/pandemos/trajectories.json?url';
+import hash from 'object-hash';
 
 export interface Agent {
   /** ID of the agent (same as index) */
@@ -58,11 +59,15 @@ export const PandemosContext = createContext<{
   agents: Crossfilter<Agent> | undefined;
   locations: Crossfilter<Location> | undefined;
   trips: Crossfilter<Trip> | undefined;
+  tripChains: Map<number, Array<Trip>> | undefined;
+  tripChainsByOccurrence: number[][] | undefined;
 }>({
   // default values should be undefined or null
   agents: undefined,
   locations: undefined,
   trips: undefined,
+  tripChains: undefined,
+  tripChainsByOccurrence: undefined,
 });
 
 // Create provider component
@@ -71,6 +76,9 @@ export const PandemosProvider = ({children}: {children: React.ReactNode}) => {
   const [locations, setLocations] = useState<Crossfilter<Location>>();
   const [trips, setTrips] = useState<Crossfilter<Trip>>();
 
+  const [tripChains, setTripChains] = useState<Map<number, Array<Trip>>>();
+  const [tripChainsByOccurrence, setTripChainsByOccurrence] = useState<Array<number[]>>();
+
   // Effect to fetch the data
   useEffect(() => {
     Promise.all([
@@ -122,15 +130,123 @@ export const PandemosProvider = ({children}: {children: React.ReactNode}) => {
     // TODO: Lazy load when the pandemos tab is selected
   }, []);
 
+  const getLocation = useCallback(
+    (id: number) => {
+      return locations?.all().find((location) => location.location_id === id);
+    },
+    [locations]
+  );
+
+  useEffect(() => {
+    const tripMap = new Map<string, Array<number>>();
+    const agentTrips = new Map<number, Array<Trip>>();
+
+    for (const trip of trips?.all() ?? []) {
+      agentTrips.set(trip.agent_id, [...(agentTrips.get(trip.agent_id) ?? []), trip]);
+    }
+
+    let tripId = 0;
+    const tripChains = new Map<number, Array<Trip>>();
+    for (const tripChain of agentTrips.values()) {
+      let start = 0;
+      tripChain.forEach((trip, index) => {
+        if (getLocation(trip.start_location)?.location_type === 0) start = index;
+        if (getLocation(trip.end_location)?.location_type === 0)
+          tripChains.set(tripId++, tripChain.slice(start, index + 1));
+      });
+    }
+
+    setTripChains(tripChains);
+
+    for (const [id, tripChain] of tripChains) {
+      const hashed: string = hash(
+        tripChain.map((trip) => ({
+          activity: trip.activity,
+          transportMode: trip.transport_mode,
+          start: getLocation(trip.start_location)?.location_type,
+          end: getLocation(trip.end_location)?.location_type,
+        }))
+      );
+
+      tripMap.set(hashed, [...(tripMap.get(hashed) ?? []), id]);
+    }
+
+    const sortedTrips = [...tripMap.values()].sort((a, b) => b.length - a.length);
+    setTripChainsByOccurrence(sortedTrips);
+
+    // TODO: Just print out the top 10 trip chains.
+    for (const chains of sortedTrips.slice(0, 10)) {
+      if (locations && chains.length > 0) {
+        console.log(chains.length);
+        printTripChain(tripChains.get(chains[0])!, locations.all());
+      }
+    }
+  }, [getLocation, locations, trips]);
+
   return (
     <PandemosContext.Provider
       value={{
         agents,
         locations,
         trips,
+        tripChains,
+        tripChainsByOccurrence: tripChainsByOccurrence,
       }}
     >
       {children}
     </PandemosContext.Provider>
   );
 };
+
+const locationNames: Record<number, string> = {
+  0: '🏡', // Home
+  1: '🏫', // School
+  2: '🏭/🏢', // Work
+  3: '💃', // Social Event
+  4: '🛒', // Shopping
+  5: '🏥🤒', // Hospital
+  6: '🏥🤮', // ICU
+  7: '🚘', // Car
+  8: '⛲', // Public
+  9: '🚍', // Transport
+  10: '⚰', // Cemetery
+};
+
+const transportNames: Record<number, string> = {
+  0: '🚴‍♀️', // Bike
+  1: '🚘D', // Car (Driver)
+  2: 'P🚘', // Car (Passenger)
+  3: '🚍', // Bus
+  4: '🚶‍♀️', // Walking
+  5: 'Other', // Other
+  6: '❓', // Unknown
+};
+
+const activityNames: Record<number, string> = {
+  0: 'Workplace',
+  1: 'Education',
+  2: 'Shopping',
+  3: 'Leisure',
+  4: 'Private Matters',
+  5: 'Other',
+  6: 'Going Home',
+  7: 'Unknown',
+};
+
+function printTripChain(tripChain: Array<Trip>, locations: Readonly<Array<Location>>) {
+  const getLocation = (id: number) => {
+    return locationNames[locations.find((location) => location.location_id === id)?.location_type ?? -1] ?? 'unknown';
+  };
+
+  console.log(`Agent: ${tripChain[0].agent_id}, Trips: ${tripChain.length}`);
+  const chainString = tripChain.reduce((previousValue: string, trip: Trip) => {
+    return (
+      previousValue +
+      ` —(${transportNames[trip.transport_mode]})⇾ ` +
+      getLocation(trip.end_location) +
+      ` [${activityNames[trip.activity]}]`
+    );
+  }, getLocation(tripChain[0].start_location));
+
+  console.log(chainString);
+}