Data update

This commit is contained in:
Ingy döt Net 2026-04-30 12:34:36 -04:00
parent 4bb20c9b71
commit cbaf4c4b64
12390 changed files with 318560 additions and 27248 deletions

View file

@ -0,0 +1,183 @@
--
-- Floyd-Warshall algorithm.
--
-- See https://en.wikipedia.org/w/index.php?title=Floyd%E2%80%93Warshall_algorithm&oldid=1082310013
--
with Ada.Containers.Vectors;
with Ada.Text_IO; use Ada.Text_IO;
with Interfaces; use Interfaces;
with Ada.Numerics.Generic_Elementary_Functions;
procedure floyd_warshall_task
is
Floyd_Warshall_Exception : exception;
-- The floating point type we shall use is one that has infinities.
subtype FloatPt is IEEE_Float_32;
package FloatPt_Elementary_Functions is new Ada.Numerics
.Generic_Elementary_Functions
(FloatPt);
use FloatPt_Elementary_Functions;
-- The following should overflow and give us an IEEE infinity. But I
-- have kept the code so you could use some non-IEEE floating point
-- format and set ENORMOUS_FloatPt to some value that is finite but
-- much larger than actual graph traversal distances.
ENORMOUS_FloatPt : constant FloatPt :=
(FloatPt (1.0) / FloatPt (1.0e-37))**1.0e37;
--
-- Input is a Vector of records representing the edges of a graph.
--
-- Vertices are identified by integers from 1 .. n.
--
type edge is record
u : Positive;
weight : FloatPt;
v : Positive;
end record;
package Edge_Vectors is new Ada.Containers.Vectors
(Index_Type => Positive, Element_Type => edge);
use Edge_Vectors;
subtype edge_vector is Edge_Vectors.Vector;
--
-- Floyd-Warshall.
--
type distance_array is
array (Positive range <>, Positive range <>) of FloatPt;
type next_vertex_array is
array (Positive range <>, Positive range <>) of Natural;
Nil_Vertex : constant Natural := 0;
function find_max_vertex -- Find the maximum vertex number.
(edges : in edge_vector)
return Positive
is
max_vertex : Positive;
begin
if Is_Empty (edges) then
raise Floyd_Warshall_Exception with "no edges";
end if;
max_vertex := 1;
for i in edges.First_Index .. edges.Last_Index loop
max_vertex := Positive'Max (max_vertex, edges.Element (i).u);
max_vertex := Positive'Max (max_vertex, edges.Element (i).v);
end loop;
return max_vertex;
end find_max_vertex;
procedure floyd_warshall -- Perform Floyd-Warshall.
(edges : in edge_vector;
max_vertex : in Positive;
distance : out distance_array;
next_vertex : out next_vertex_array)
is
u, v : Positive;
dist_ikj : FloatPt;
begin
-- Initialize.
for i in 1 .. max_vertex loop
for j in 1 .. max_vertex loop
distance (i, j) := ENORMOUS_FloatPt;
next_vertex (i, j) := Nil_Vertex;
end loop;
end loop;
for i in edges.First_Index .. edges.Last_Index loop
u := edges.Element (i).u;
v := edges.Element (i).v;
distance (u, v) := edges.Element (i).weight;
next_vertex (u, v) := v;
end loop;
for i in 1 .. max_vertex loop
distance (i, i) :=
FloatPt (0.0); -- Distance from a vertex to itself.
next_vertex (i, i) := i;
end loop;
-- Perform the algorithm.
for k in 1 .. max_vertex loop
for i in 1 .. max_vertex loop
for j in 1 .. max_vertex loop
dist_ikj := distance (i, k) + distance (k, j);
if dist_ikj < distance (i, j) then
distance (i, j) := dist_ikj;
next_vertex (i, j) := next_vertex (i, k);
end if;
end loop;
end loop;
end loop;
end floyd_warshall;
--
-- Path reconstruction.
--
procedure put_path
(next_vertex : in next_vertex_array;
u, v : in Positive)
is
i : Positive;
begin
if next_vertex (u, v) /= Nil_Vertex then
i := u;
Put (Positive'Image (i));
while i /= v loop
Put (" ->");
i := next_vertex (i, v);
Put (Positive'Image (i));
end loop;
end if;
end put_path;
example_graph : edge_vector;
max_vertex : Positive;
begin
Append (example_graph, (u => 1, weight => FloatPt (-2.0), v => 3));
Append (example_graph, (u => 3, weight => FloatPt (+2.0), v => 4));
Append (example_graph, (u => 4, weight => FloatPt (-1.0), v => 2));
Append (example_graph, (u => 2, weight => FloatPt (+4.0), v => 1));
Append (example_graph, (u => 2, weight => FloatPt (+3.0), v => 3));
max_vertex := find_max_vertex (example_graph);
declare
distance : distance_array (1 .. max_vertex, 1 .. max_vertex);
next_vertex : next_vertex_array
(1 .. max_vertex, 1 .. max_vertex);
begin
floyd_warshall (example_graph, max_vertex, distance, next_vertex);
Put_Line (" pair distance path");
Put_Line ("---------------------------------------------");
for u in 1 .. max_vertex loop
for v in 1 .. max_vertex loop
if u /= v then
Put (Positive'Image (u));
Put (" ->");
Put (Positive'Image (v));
Put (" ");
Put (FloatPt'Image (distance (u, v)));
Put (" ");
put_path (next_vertex, u, v);
Put_Line ("");
end if;
end loop;
end loop;
end;
end floyd_warshall_task;

View file

@ -0,0 +1,183 @@
IDENTIFICATION DIVISION.
PROGRAM-ID. FLOYD-WARSHALL.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-NUM-VERTICES PIC 9 VALUE 4.
01 WS-NUM-WEIGHTS PIC 9 VALUE 5.
01 WS-INFINITY PIC 9(7)V9(2) VALUE 9999999.99.
01 WS-WEIGHTS.
05 WS-W OCCURS 5 TIMES.
10 WS-FROM PIC 9.
10 WS-TO PIC 9.
10 WS-COST PIC S9(3) SIGN LEADING SEPARATE.
01 WS-DIST.
05 WS-D OCCURS 4 TIMES.
10 WS-D-COL OCCURS 4 TIMES.
15 WS-DIST-VAL PIC S9(7)V9(2).
01 WS-NEXT.
05 WS-N OCCURS 4 TIMES.
10 WS-N-COL OCCURS 4 TIMES.
15 WS-NEXT-VAL PIC 9.
01 WS-I PIC 9.
01 WS-J PIC 9.
01 WS-K PIC 9.
01 WS-U PIC 9.
01 WS-V PIC 9.
01 WS-IDX PIC 9.
01 WS-TEMP-SUM PIC S9(7)V9(2).
01 WS-DIST-IJ PIC S9(7)V9(2).
01 WS-DIST-IK PIC S9(7)V9(2).
01 WS-DIST-KJ PIC S9(7)V9(2).
*> Path and display working fields
01 WS-PATH PIC X(200).
01 WS-PATH-TEMP PIC X(200).
01 WS-DIST-INT PIC S9(5).
01 WS-DIST-EDIT PIC -(4)9.
01 WS-DIST-TRIM PIC X(6).
01 WS-OUTPUT-LINE PIC X(80).
01 WS-NODE-CHAR PIC 9.
PROCEDURE DIVISION.
MAIN-PARA.
MOVE 1 TO WS-FROM(1)
MOVE 3 TO WS-TO(1)
MOVE -2 TO WS-COST(1)
MOVE 2 TO WS-FROM(2)
MOVE 1 TO WS-TO(2)
MOVE 4 TO WS-COST(2)
MOVE 2 TO WS-FROM(3)
MOVE 3 TO WS-TO(3)
MOVE 3 TO WS-COST(3)
MOVE 3 TO WS-FROM(4)
MOVE 4 TO WS-TO(4)
MOVE 2 TO WS-COST(4)
MOVE 4 TO WS-FROM(5)
MOVE 2 TO WS-TO(5)
MOVE -1 TO WS-COST(5)
PERFORM INIT-DIST
PERFORM INIT-NEXT
PERFORM FLOYD-WARSHALL
PERFORM PRINT-RESULT
STOP RUN.
INIT-DIST.
PERFORM VARYING WS-I FROM 1 BY 1
UNTIL WS-I > WS-NUM-VERTICES
PERFORM VARYING WS-J FROM 1 BY 1
UNTIL WS-J > WS-NUM-VERTICES
MOVE WS-INFINITY TO WS-DIST-VAL(WS-I, WS-J)
END-PERFORM
END-PERFORM
PERFORM VARYING WS-IDX FROM 1 BY 1
UNTIL WS-IDX > WS-NUM-WEIGHTS
MOVE WS-FROM(WS-IDX) TO WS-I
MOVE WS-TO(WS-IDX) TO WS-J
MOVE WS-COST(WS-IDX) TO WS-DIST-VAL(WS-I, WS-J)
END-PERFORM.
INIT-NEXT.
PERFORM VARYING WS-I FROM 1 BY 1
UNTIL WS-I > WS-NUM-VERTICES
PERFORM VARYING WS-J FROM 1 BY 1
UNTIL WS-J > WS-NUM-VERTICES
IF WS-I NOT EQUAL WS-J
MOVE WS-J TO WS-NEXT-VAL(WS-I, WS-J)
ELSE
MOVE 0 TO WS-NEXT-VAL(WS-I, WS-J)
END-IF
END-PERFORM
END-PERFORM.
FLOYD-WARSHALL.
PERFORM VARYING WS-K FROM 1 BY 1
UNTIL WS-K > WS-NUM-VERTICES
PERFORM VARYING WS-I FROM 1 BY 1
UNTIL WS-I > WS-NUM-VERTICES
PERFORM VARYING WS-J FROM 1 BY 1
UNTIL WS-J > WS-NUM-VERTICES
MOVE WS-DIST-VAL(WS-I, WS-K) TO WS-DIST-IK
MOVE WS-DIST-VAL(WS-K, WS-J) TO WS-DIST-KJ
MOVE WS-DIST-VAL(WS-I, WS-J) TO WS-DIST-IJ
IF WS-DIST-IK < WS-INFINITY AND
WS-DIST-KJ < WS-INFINITY
COMPUTE WS-TEMP-SUM =
WS-DIST-IK + WS-DIST-KJ
IF WS-TEMP-SUM < WS-DIST-IJ
MOVE WS-TEMP-SUM
TO WS-DIST-VAL(WS-I, WS-J)
MOVE WS-NEXT-VAL(WS-I, WS-K)
TO WS-NEXT-VAL(WS-I, WS-J)
END-IF
END-IF
END-PERFORM
END-PERFORM
END-PERFORM.
PRINT-RESULT.
DISPLAY "pair dist path"
PERFORM VARYING WS-I FROM 1 BY 1
UNTIL WS-I > WS-NUM-VERTICES
PERFORM VARYING WS-J FROM 1 BY 1
UNTIL WS-J > WS-NUM-VERTICES
IF WS-I NOT EQUAL WS-J
*> Set up source and destination
MOVE WS-I TO WS-U
MOVE WS-J TO WS-V
*> Seed path with just the source node
MOVE SPACES TO WS-PATH
MOVE WS-I TO WS-NODE-CHAR
MOVE WS-NODE-CHAR TO WS-PATH(1:1)
*> Walk next-hop until we reach destination
PERFORM UNTIL WS-U = WS-V
MOVE WS-NEXT-VAL(WS-U, WS-V) TO WS-U
MOVE WS-U TO WS-NODE-CHAR
MOVE SPACES TO WS-PATH-TEMP
STRING
FUNCTION TRIM(WS-PATH TRAILING)
DELIMITED SIZE
" -> " DELIMITED SIZE
WS-NODE-CHAR DELIMITED SIZE
INTO WS-PATH-TEMP
MOVE WS-PATH-TEMP TO WS-PATH
END-PERFORM
*> Format distance: move to integer then edit picture
*> to get clean signed number without leading zeros
COMPUTE WS-DIST-INT =
WS-DIST-VAL(WS-I, WS-J)
MOVE WS-DIST-INT TO WS-DIST-EDIT
MOVE FUNCTION TRIM(WS-DIST-EDIT LEADING)
TO WS-DIST-TRIM
*> Assemble and print output line
MOVE SPACES TO WS-OUTPUT-LINE
STRING
WS-I DELIMITED SIZE
" -> " DELIMITED SIZE
WS-J DELIMITED SIZE
" " DELIMITED SIZE
FUNCTION TRIM(WS-DIST-TRIM LEADING)
DELIMITED SIZE
" " DELIMITED SIZE
FUNCTION TRIM(WS-PATH TRAILING)
DELIMITED SIZE
INTO WS-OUTPUT-LINE
DISPLAY FUNCTION TRIM(WS-OUTPUT-LINE TRAILING)
END-IF
END-PERFORM
END-PERFORM.