add circulation problem resolution

.gitignore

@@ -1,4 +1,7 @@
 _build/
 ftest.native
+circulationtest.native
 outfile
-*~
+*~
+test/
+run/

Makefile

@@ -20,33 +20,44 @@ edit:
 
 demo: build
 	@echo $(EXECUTING)
-	./ftest.native graphs/graph1 1 2 outfile
+	./ftest.native graphs/graph1 1 2 test/outfile
 	@echo $(RESULT)
-	@cat outfile
+	@cat test/outfile
 
 test: build
 	@echo $(EXECUTING)
-	./ftest.native graphs/graph1 1 2 outfile
+	./ftest.native graphs/graph1 1 2 test/outfile
 	@echo $(BUILDING_SVG)
 	@echo "outfile..."
-	@dot -Tsvg outfile > outfile.svg
+	@dot -Tsvg test/outfile > test/outfile.svg
 	@echo "graph_init..."
-	@dot -Tsvg graph_init > graph_init.svg
+	@dot -Tsvg test/graph_init > test/graph_init.svg
 	@echo "graph_apply..."
-	@dot -Tsvg graph_apply > graph_apply.svg
+	@dot -Tsvg test/graph_apply > test/graph_apply.svg
 	@echo "graph_res..."
-	@dot -Tsvg graph_res > graph_res.svg
+	@dot -Tsvg test/graph_res > test/graph_res.svg
 	@echo ""
 
 run: build
 	@echo $(EXECUTING)
-	./ftest.native graphs/test1 0 3 solution
+	./ftest.native graphs/test2 0 5 run/solution
 	@echo $(BUILDING_SVG)
 	@echo "solution..."
-	@dot -Tsvg solution > solution.svg
+	@dot -Tsvg run/solution > run/solution.svg
 	@echo ""
 
 
 clean:
 	-rm -rf _build/
 	-rm ftest.native
+
+build_circulation: 
+	@echo $(COMPILING)
+	ocamlbuild circulationtest.native
+
+run_circulation: build_circulation
+	@echo $(EXECUTING)
+	./circulationtest.native circulation_input_graphs/test1 run/circulation_solution
+	@echo $(BUILDING_SVG)
+	@echo "solution..."
+	@dot -Tsvg run/circulation_solution > run/circulation_solution.svg

circulation_input_graphs/test1

@@ -0,0 +1,27 @@
+% Factories
+% factory id production_rate 
+factory 0 6
+factory 1 6
+
+% Villages
+% village id demand
+village 5 10
+village 6 10
+village 7 10
+
+% n id
+node 2
+node 3
+node 4
+
+road 0 1 2
+road 0 2 4
+road 0 3 4
+road 1 2 3
+road 1 4 3
+road 2 3 5
+road 4 3 3
+road 4 5 1
+road 4 6 5
+road 2 6 4
+road 2 7 1

graphs/test2

@@ -0,0 +1,15 @@
+% Graph saved at Fri Nov 20 2020 14:11:39 GMT+0100 (Central European Standard Time)
+n 130 200
+n 225 300
+n 325 300
+n 175 100
+n 275 100
+n 370 200
+e 0 1 15
+e 1 2 12
+e 2 5 7
+e 0 3 4
+e 3 4 10
+e 4 5 10
+e 2 3 3
+e 4 1 5

outfile.svg

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src/circulationfile.ml

@@ -0,0 +1,100 @@
+open Graph
+open Printf
+open Ffalgo
+
+type path = string
+
+(* Format of text files:
+   % This is a comment
+
+   % A node with its coordinates (which are not used).
+   n 88.8 209.7
+   n 408.9 183.0
+
+   % The first node has id 0, the next is 1, and so on.
+
+   % Edges: e source dest label
+   e 3 1 11
+   e 0 2 8
+
+*)
+
+let source = (-1)
+let destination = (-2)
+
+let read_factory graph line =
+  try Scanf.sscanf line "factory %d %d" (fun id capacity -> new_arc (new_node graph id) source id capacity)
+  with e ->
+    Printf.printf "Cannot read factory in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+let read_village graph line =
+  try Scanf.sscanf line "village %d %d" (fun id capacity -> new_arc (new_node graph id) id destination capacity)
+  with e ->
+    Printf.printf "Cannot read village in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+(* Reads a line with a node. *)
+let read_node graph line =
+  try Scanf.sscanf line "node %d" (fun id -> new_node graph id)
+  with e ->
+    Printf.printf "Cannot read node in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+(* Ensure that the given node exists in the graph. If not, create it. 
+ * (Necessary because the website we use to create online graphs does not generate correct files when some nodes have been deleted.) *)
+let ensure graph id = if node_exists graph id then graph else new_node graph id
+
+(* Reads a line with an arc. *)
+let read_road graph line =
+  try Scanf.sscanf line "road %d %d %d"
+        (fun id1 id2 capacity -> new_arc (ensure (ensure graph id1) id2) id1 id2 capacity)
+  with e ->
+    Printf.printf "Cannot read arc in line - %s:\n%s\n%!" (Printexc.to_string e) line ;
+    failwith "from_file"
+
+(* Reads a comment or fail. *)
+let read_comment graph line =
+  try Scanf.sscanf line " %%" graph
+  with _ ->
+    Printf.printf "Unknown line:\n%s\n%!" line ;
+    failwith "from_file"
+
+let circulation_from_file path =
+
+  let infile = open_in path in
+  (* create source and destination *)
+  let initial_graph = new_node (new_node empty_graph source) destination in
+  (* Read all lines until end of file. 
+   * n is the current node counter. *)
+  let rec loop graph =
+    try
+      let line = input_line infile in
+
+      (* Remove leading and trailing spaces. *)
+      let line = String.trim line in
+
+      let graph2 =
+        (* Ignore empty lines *)
+        if line = "" then graph
+
+        (* The first character of a line determines its content : n or e. *)
+        else match line.[0] with
+          | 'f' -> read_factory graph line
+          | 'v' -> read_village graph line
+          | 'n' -> read_node graph line
+          | 'r' -> read_road graph line
+
+          (* It should be a comment, otherwise we complain. *)
+          | _ -> read_comment graph line
+      in      
+      loop graph2
+
+    with End_of_file -> graph (* Done *)
+  in
+
+  let final_graph = loop initial_graph in
+
+  close_in infile ;
+  {graph = final_graph; origin = source; destination = destination}
+

src/circulationfile.mli

@@ -0,0 +1,11 @@
+(* Read a graph from a file,
+ * Write a graph to a file. *)
+
+open Graph
+open Ffalgo
+
+type path = string
+
+val circulation_from_file: path -> int network
+
+

src/circulationtest.ml

@@ -0,0 +1,38 @@
+open Circulationfile
+open Gfile
+open Tools
+open Ffalgo
+
+
+let flow_to_string gr = gmap gr (fun fl -> String.concat "/" [(string_of_int fl.current); (string_of_int fl.capacity)])
+
+let () =
+
+  (* Check the number of command-line arguments *)
+  if Array.length Sys.argv <> 3 then
+    begin
+      Printf.printf "\nUsage: %s infile outfile\n\n%!" Sys.argv.(0) ;
+      exit 0
+    end ;
+
+
+  (* Arguments are : infile(1) source-id(2) sink-id(3) outfile(4) *)
+
+  let infile = Sys.argv.(1)
+  and outfile = Sys.argv.(2)
+  in
+
+  (* Open file *)
+  let initial_network = circulation_from_file infile in
+  (* Execute FF *)
+  let solution_network = run_ff initial_network in
+  (* Print max flow *)
+  let () = Printf.printf "Max flow: %d\n%!" (get_max_flow solution_network) in
+  (* Convert to string for export *)
+  let final_graph = flow_to_string solution_network.graph in
+
+  (* Rewrite the graph that has been read. *)
+  let () = export outfile final_graph in
+
+  ()
+