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Version: 1.8.1

7. Automatic Road Repair

This 7th step illustrates how to select in a list of elements that optimizes a given function.

Formulation

  • Add a new parameter, repair_time, that is equal to 2.
  • Every repair_time, the road with the highest destruction_coeff value is repaired (set its destruction_coeff to 1).

Model Definition

parameters

We add a new parameter: the repair_time.

In the global section, we define the repair_time variable:

int repair_time <- 2 ;

In the experiment section, we define the associated parameter:

parameter "Number of steps between two road repairs" var: repair_time category: "Road" ;

road repairing

We have to add a reflex method in the global section that is triggered every repair_time hours. This reflex selects, thanks to the with_max_of operator the road agent with the highest destruction_coeff value, then sets this value at 1.

global {
...
reflex repair_road when: every(repair_time #hour) {
road the_road_to_repair <- road with_max_of (each.destruction_coeff) ;
ask the_road_to_repair {
destruction_coeff <- 1.0 ;
}
}
}

Complete Model

model tutorial_gis_city_traffic

global {
file shape_file_buildings <- file("../includes/building.shp");
file shape_file_roads <- file("../includes/road.shp");
file shape_file_bounds <- file("../includes/bounds.shp");
geometry shape <- envelope(shape_file_bounds);
float step <- 10 #mn;
date starting_date <- date("2019-09-01-00-00-00");
int nb_people <- 100;
int min_work_start <- 6;
int max_work_start <- 8;
int min_work_end <- 16;
int max_work_end <- 20;
float min_speed <- 1.0 #km / #h;
float max_speed <- 5.0 #km / #h;
float destroy <- 0.02;
int repair_time <- 2 ;
graph the_graph;

init {
create building from: shape_file_buildings with: [type::string(read ("NATURE"))] {
if type="Industrial" {
color <- #blue ;
}
}
create road from: shape_file_roads ;
map<road,float> weights_map <- road as_map (each:: (each.destruction_coeff * each.shape.perimeter));
the_graph <- as_edge_graph(road) with_weights weights_map;

list<building> residential_buildings <- building where (each.type="Residential");
list<building> industrial_buildings <- building where (each.type="Industrial") ;
create people number: nb_people {
speed <- rnd(min_speed, max_speed);
start_work <- rnd (min_work_start, max_work_start);
end_work <- rnd(min_work_end, max_work_end);
living_place <- one_of(residential_buildings) ;
working_place <- one_of(industrial_buildings) ;
objective <- "resting";
location <- any_location_in (living_place);
}
}

reflex update_graph{
map<road,float> weights_map <- road as_map (each:: (each.destruction_coeff * each.shape.perimeter));
the_graph <- the_graph with_weights weights_map;
}

reflex repair_road when: every(repair_time #hour ) {
road the_road_to_repair <- road with_max_of (each.destruction_coeff) ;
ask the_road_to_repair {
destruction_coeff <- 1.0 ;
}
}
}

species building {
string type;
rgb color <- #gray ;

aspect base {
draw shape color: color ;
}
}

species road {
float destruction_coeff <- rnd(1.0,2.0) max: 2.0;
int colorValue <- int(255*(destruction_coeff - 1)) update: int(255*(destruction_coeff - 1));
rgb color <- rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) update: rgb(min([255, colorValue]),max ([0, 255 - colorValue]),0) ;

aspect base {
draw shape color: color ;
}
}

species people skills:[moving] {
rgb color <- #yellow ;
building living_place <- nil ;
building working_place <- nil ;
int start_work ;
int end_work ;
string objective ;
point the_target <- nil ;

reflex time_to_work when: current_date.hour = start_work and objective = "resting"{
objective <- "working" ;
the_target <- any_location_in (working_place);
}

reflex time_to_go_home when: current_date.hour = end_work and objective = "working"{
objective <- "resting" ;
the_target <- any_location_in (living_place);
}

reflex move when: the_target != nil {
path path_followed <- goto(target: the_target, on:the_graph, return_path: true);
list<geometry> segments <- path_followed.segments;
loop line over: segments {
float dist <- line.perimeter;
ask road(path_followed agent_from_geometry line) {
destruction_coeff <- destruction_coeff + (destroy * dist / shape.perimeter);
}
}
if the_target = location {
the_target <- nil ;
}
}

aspect base {
draw circle(10) color: color border: #black;
}
}

experiment road_traffic type: gui {
parameter "Shapefile for the buildings:" var: shape_file_buildings category: "GIS" ;
parameter "Shapefile for the roads:" var: shape_file_roads category: "GIS" ;
parameter "Shapefile for the bounds:" var: shape_file_bounds category: "GIS" ;
parameter "Number of people agents" var: nb_people category: "People" ;
parameter "Earliest hour to start work" var: min_work_start category: "People" min: 2 max: 8;
parameter "Latest hour to start work" var: max_work_start category: "People" min: 8 max: 12;
parameter "Earliest hour to end work" var: min_work_end category: "People" min: 12 max: 16;
parameter "Latest hour to end work" var: max_work_end category: "People" min: 16 max: 23;
parameter "minimal speed" var: min_speed category: "People" min: 0.1 #km/#h ;
parameter "maximal speed" var: max_speed category: "People" max: 10 #km/#h;
parameter "Value of destruction when a people agent takes a road" var: destroy category: "Road" ;
parameter "Number of hours between two road repairs" var: repair_time category: "Road" ;

output {
display city_display type:opengl {
species building aspect: base ;
species road aspect: base ;
species people aspect: base ;
}
display chart_display refresh: every(10#cycles) {
chart "Road Status" type: series size: {1, 0.5} position: {0, 0} {
data "Mean road destruction" value: mean (road collect each.destruction_coeff) style: line color: #green ;
data "Max road destruction" value: road max_of each.destruction_coeff style: line color: #red ;
}
chart "People Objectif" type: pie style: exploded size: {1, 0.5} position: {0, 0.5}{
data "Working" value: people count (each.objective="working") color: #magenta ;
data "Resting" value: people count (each.objective="resting") color: #blue ;
}
}
}
}