Slightly improvre speed by including some boundary conditions inside …

…appproximate lookahead
jedlimlx · May 9, 2024 · 4d1b37c · 4d1b37c
1 parent de8d42d
commit 4d1b37c
Show file tree

Hide file tree

Showing 2 changed files with 27 additions and 16 deletions.
diff --git a/src/commonMain/kotlin/search/cfind/CFind.kt b/src/commonMain/kotlin/search/cfind/CFind.kt
@@ -94,7 +94,7 @@ class CFind(
             count += this[count.mod(period)]
         }
 
-        this[count.mod(period)] = (backoffPeriod - count).fmod(backoffPeriod)
+        this[count.mod(period)] = period * k - count
     }
     val fwdOff = run {
         val array = IntArray(period) { -1 }
@@ -336,7 +336,7 @@ class CFind(
     val maxWidth: Int = widthsByHeight.slice(0 .. this.lookaheadDepth).maxOf { it }
 
     // TODO fix approximate lookahead for spacing != 1
-    val approximateLookahead = spacing == 1 && false && lookaheadDepth > 0 && lookaheadIndices[0][0].last() != 0
+    val approximateLookahead = spacing == 1 && lookaheadDepth > 0 && lookaheadIndices[0][0].last() != 0
 
     // Computing neighbourhoods to be memorised for lookahead
     val memorisedlookaheadNeighbourhood: List<List<Pair<Coordinate, Int>>> = lookaheadIndices.indices.map {
@@ -420,7 +420,7 @@ class CFind(
         }
     }
 
-    val combinedSuccessorArray: BooleanArray = run {
+    val combinedSuccessorArray: IntArray = run {
         if (verbosity >= 0 && !stdin) {
             t.cursor.move {
                 up(1)
@@ -431,19 +431,28 @@ class CFind(
         }
         println("Generating approximate lookahead lookup table...", verbosity = 0)
 
-        BooleanArray(
+        IntArray(
             pow(rule.numStates, neighbourhood[0].size - baseCoordinates.size + 2)
         ) {
-
-            var output = false
-            for (i in successorTable[it].indices) {
-                if (successorTable[it][i] != 0) {
-                    output = true
-                    break
+            var num = 0
+            for (j in 0..reversedBaseCoordinate.size) {
+                var output = false
+                for (i in successorTable[it].indices) {
+                    if (
+                        (
+                            j == reversedBaseCoordinate.size || 
+                            i and ((2 shl (reversedBaseCoordinate.size - j - 1)) - 1) shl j == 0
+                        ) && successorTable[it][i] != 0
+                    ) {
+                        output = true
+                        break
+                    }
                 }
+
+                if (output) num += 1 shl j
             }
 
-            output
+            num
         }
     }
 
@@ -1513,7 +1522,7 @@ class CFind(
         val approximateLookaheadRows: List<Row?>
         val lookaheadDepthDiff = if (lookaheadDepth < this.lookaheadDepth) {
             approximateLookaheadRows = lookaheadRows[0]
-            if (lookaheadDepth - 1 >= 0) {
+            if (lookaheadDepth >= 1) {
                 lookaheadIndices[lookaheadDepth - 1][depth.mod(period)].filter { it > 0 }.min()
             } else minIndices[depth.mod(period)]
         } else {
@@ -1553,7 +1562,7 @@ class CFind(
             power *= rule.numStates
 
             key += approximateLookaheadRows[coordinate, 1, null, depth] * power
-            return combinedSuccessorArray[key]
+            return combinedSuccessorArray[key] and (1 shl minOf(index, reversedBaseCoordinate.size)) != 0
         }
 
         // Checks boundary conditions

diff --git a/src/jvmMain/kotlin/Main.jvm.kt b/src/jvmMain/kotlin/Main.jvm.kt
@@ -123,9 +123,11 @@ actual fun main() {
 
     // B2-ei3cjkr4cektyz5-cnr6-ik78/S01e2-ae3cnqry4cqrtwyz5-ain6ekn7e
     val search = CFind(  
-        HROT("R2,C2,S2-3,B3,N@891891"), 4, 3, 10, ShipSymmetry.GLIDE,
-        verbosity = 1, searchStrategy = SearchStrategy.PRIORITY_QUEUE, direction = Coordinate(1, 1),
-        lookaheadDepth = 1//, isotropic = false
+        HROT("R3,C2,S6-9,B7-8,NN"), 2, 1, 8, ShipSymmetry.EVEN,
+        verbosity = 1, searchStrategy = SearchStrategy.HYBRID_BFS, 
+        numShips = 1
+        //direction = Coordinate(1, 1),
+        //lookaheadDepth = 1, //, isotropic = false
     )
     search.search()