Data update

Task/Evolutionary-algorithm/Pascal/evolutionary-algorithm.pas

@@ -1,108 +1,108 @@
 PROGRAM EVOLUTION (OUTPUT);
 
 CONST
-	TARGET = 'METHINKS IT IS LIKE A WEASEL';
-	COPIES = 100;  (* 100 children in each generation. *)
-	RATE = 1000;  (* About one character in 1000 will be a mutation. *)
+    TARGET = 'METHINKS IT IS LIKE A WEASEL';
+    COPIES = 100;  (* 100 children in each generation. *)
+    RATE = 1000;  (* About one character in 1000 will be a mutation. *)
 
 TYPE
-	STRLIST = ARRAY [1..COPIES] OF STRING;
+    STRLIST = ARRAY [1..COPIES] OF STRING;
 
 FUNCTION RANDCHAR : CHAR;
  (* Generate a random letter or space. *)
  VAR RANDNUM : INTEGER;
  BEGIN
-	RANDNUM := RANDOM(27);
-	IF RANDNUM = 26 THEN
-		RANDCHAR := ' '
-	ELSE
-		RANDCHAR := CHR(RANDNUM + ORD('A'))
+    RANDNUM := RANDOM(27);
+    IF RANDNUM = 26 THEN
+        RANDCHAR := ' '
+    ELSE
+        RANDCHAR := CHR(RANDNUM + ORD('A'))
  END;
 
 FUNCTION RANDSTR (SIZE : INTEGER) : STRING;
  (* Generate a random string. *)
  VAR
-	N : INTEGER;
-	S : STRING;
+    N : INTEGER;
+    S : STRING;
  BEGIN
-	S := '';
-	FOR N := 1 TO SIZE DO
-		INSERT(RANDCHAR, S, 1);
-	RANDSTR := S
+    S := '';
+    FOR N := 1 TO SIZE DO
+        INSERT(RANDCHAR, S, 1);
+    RANDSTR := S
  END;
 
 FUNCTION FITNESS (CANDIDATE, GOAL : STRING) : INTEGER;
  (* Count the number of correct letters in the correct places *)
  VAR N, MATCHES : INTEGER;
  BEGIN
-	MATCHES := 0;
-	FOR N := 1 TO LENGTH(GOAL) DO
-		IF CANDIDATE[N] = GOAL[N] THEN
-			MATCHES := MATCHES + 1;
-	FITNESS := MATCHES
+    MATCHES := 0;
+    FOR N := 1 TO LENGTH(GOAL) DO
+        IF CANDIDATE[N] = GOAL[N] THEN
+            MATCHES := MATCHES + 1;
+    FITNESS := MATCHES
  END;
 
 FUNCTION MUTATE (RATE : INTEGER; S : STRING) : STRING;
  (* Randomly alter a string. Characters change with probability 1/RATE. *)
  VAR
-	N : INTEGER;
-	CHANGE : BOOLEAN;
+    N : INTEGER;
+    CHANGE : BOOLEAN;
  BEGIN
-	FOR N := 1 TO LENGTH(TARGET) DO
-	 BEGIN
-		CHANGE := RANDOM(RATE) = 0;
-		IF CHANGE THEN
-			S[N] := RANDCHAR
-	 END;
-	MUTATE := S
+    FOR N := 1 TO LENGTH(TARGET) DO
+     BEGIN
+        CHANGE := RANDOM(RATE) = 0;
+        IF CHANGE THEN
+            S[N] := RANDCHAR
+     END;
+    MUTATE := S
  END;
 
 PROCEDURE REPRODUCE (RATE : INTEGER; PARENT : STRING; VAR CHILDREN : STRLIST);
  (* Generate children with random mutations. *)
  VAR N : INTEGER;
  BEGIN
-	FOR N := 1 TO COPIES DO
-		CHILDREN[N] := MUTATE(RATE, PARENT)
+    FOR N := 1 TO COPIES DO
+        CHILDREN[N] := MUTATE(RATE, PARENT)
  END;
 
 FUNCTION FITTEST(CHILDREN : STRLIST; GOAL : STRING) : STRING;
  (* Measure the fitness of each child and return the fittest. *)
  (* If multiple children equally match the target, then return the first. *)
  VAR
-	MATCHES, MOST_MATCHES, BEST_INDEX, N : INTEGER;
+    MATCHES, MOST_MATCHES, BEST_INDEX, N : INTEGER;
  BEGIN
-	MOST_MATCHES := 0;
-	BEST_INDEX := 1;
-	FOR N := 1 TO COPIES DO
-	 BEGIN
-		MATCHES := FITNESS(CHILDREN[N], GOAL);
-		IF MATCHES > MOST_MATCHES THEN
-		 BEGIN
-			MOST_MATCHES := MATCHES;
-			BEST_INDEX := N
-		 END
-	 END;
-	FITTEST := CHILDREN[BEST_INDEX]
+    MOST_MATCHES := 0;
+    BEST_INDEX := 1;
+    FOR N := 1 TO COPIES DO
+     BEGIN
+        MATCHES := FITNESS(CHILDREN[N], GOAL);
+        IF MATCHES > MOST_MATCHES THEN
+         BEGIN
+            MOST_MATCHES := MATCHES;
+            BEST_INDEX := N
+         END
+     END;
+    FITTEST := CHILDREN[BEST_INDEX]
  END;
 
 VAR
-	PARENT, BEST_CHILD : STRING;
-	CHILDREN : STRLIST;
-	GENERATIONS : INTEGER;
+    PARENT, BEST_CHILD : STRING;
+    CHILDREN : STRLIST;
+    GENERATIONS : INTEGER;
 
 BEGIN
-	RANDOMIZE;
-	GENERATIONS := 0;
-	PARENT := RANDSTR(LENGTH(TARGET));
-	WHILE NOT (PARENT = TARGET) DO
-	 BEGIN
-		IF (GENERATIONS MOD 100) = 0 THEN WRITELN(PARENT);
-		GENERATIONS := GENERATIONS + 1;
-		REPRODUCE(RATE, PARENT, CHILDREN);
-		BEST_CHILD := FITTEST(CHILDREN, TARGET);
-		IF FITNESS(PARENT, TARGET) < FITNESS(BEST_CHILD, TARGET) THEN
-			PARENT := BEST_CHILD
-	 END;
-	WRITE('The string was matched in ');
-	WRITELN(GENERATIONS, ' generations.')
+    RANDOMIZE;
+    GENERATIONS := 0;
+    PARENT := RANDSTR(LENGTH(TARGET));
+    WHILE NOT (PARENT = TARGET) DO
+     BEGIN
+        IF (GENERATIONS MOD 100) = 0 THEN WRITELN(PARENT);
+        GENERATIONS := GENERATIONS + 1;
+        REPRODUCE(RATE, PARENT, CHILDREN);
+        BEST_CHILD := FITTEST(CHILDREN, TARGET);
+        IF FITNESS(PARENT, TARGET) < FITNESS(BEST_CHILD, TARGET) THEN
+            PARENT := BEST_CHILD
+     END;
+    WRITE('The string was matched in ');
+    WRITELN(GENERATIONS, ' generations.')
 END.