fix redundancy checker to consider mirrored rules as well

All equivalent representations of the same rule should yield the same
outcome as to whether the rule contains redundant adjacencies.

This now finds about 127k additional redundant rules.

Author: memo33

src/main/scala/scripts/RedundantAdjacenciesChecker.scala

@@ -132,8 +132,8 @@ object RedundantAdjacenciesChecker extends Rul2Checker {
   }
 
   def isRedundantAdjacency(rule: Rule[IdTile], lookupRule: PartialFunction[EquivRule, Rule[IdTile]]): Boolean = {
-    val a = rule(0)
-    def checkOrth() = {
+    def checkOrth(rule: Rule[IdTile]) = {
+      val a = rule(0)
       val c = rule(1)
       orthogonalSurrogateTiles.exists { b =>
         if (b.id == a.id || b.id == c.id) {  // this would depend on the same rule
@@ -144,7 +144,8 @@ object RedundantAdjacenciesChecker extends Rul2Checker {
         }
       }
     }
-    def checkDiag() = {
+    def checkDiag(rule: Rule[IdTile]) = {
+      val a = rule(0)
       val d = rule(1)
       diagonalSurrogateTiles.exists { case (b, c, southBound) =>
         if (c.id == a.id || b.id == d.id) {  // this would depend on the same rule
@@ -155,7 +156,10 @@ object RedundantAdjacenciesChecker extends Rul2Checker {
         }
       }
     }
-    checkOrth() || checkDiag()
+    checkOrth(rule) || checkDiag(rule) || {
+      val ruleFlipped = rule.map(_ * R2F1)  // checking the flipped rule is important to ensure that two equivalent rules are both either redundant or not
+      checkOrth(ruleFlipped) || checkDiag(ruleFlipped)
+    }
   }
 
 }