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Re-write algorithm to compute lookahead indices
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@jedlimlx
jedlimlx committed May 14, 2024
1 parent d68f37c commit 40efc2d
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Showing 2 changed files with 64 additions and 33 deletions.
88 changes: 59 additions & 29 deletions src/commonMain/kotlin/search/cfind/CFind.kt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -159,7 +159,7 @@ class CFind(
var index = 0
while (count < period * k) {
val rem = count % period
for (i in 0 ..<k) this[rem] = rule.background[index]
for (i in 0 ..<k) this[rem+i*period] = rule.background[index % rule.background.size]
count += backOff[count.mod(period)]
index++
}
Expand Down Expand Up @@ -288,28 +288,28 @@ class CFind(
val minIndices = indices.map { it.min() }

private val tempIndices = run {
val lst = arrayListOf(indices)
for (i in indices[0].distinct().indices) {
lst.add(
Array(period) { phase ->
val temp = if (lst.last()[phase].count { it > 0 } > 0)
lst.last()[phase].filter { it > 0 }.min()
else 0
val pos = lst.last()[phase].indexOf(temp)

if (pos < indices[0].size - 1) lst.last()[phase].map { it - temp }.toIntArray()
else {
val fwdOffset = fwdOff[phase.mod(period)]
lst.last()[phase].map {
if (it - temp != 0) it - (period - fwdOffset)
else 0
}.toIntArray()
}
val lst = Array(period) { phase ->
val temp = arrayListOf<IntArray>()
val unknown = hashSetOf<Int>(0)
for (i in 1 .. indices[0].max()) {
val output = indices[(phase + i).mod(period)].map { it - i }.toIntArray()
if ((output.toSet() intersect unknown).isNotEmpty()) {
unknown.add(output.first() - indices[0][0])
temp.add(output)
}
)
}
}

lst.subList(1, lst.size)
temp.toTypedArray()
}

// TODO refactor so period is first
val output = Array(lst.map { it.size }.min()) { depth ->
Array(period) { phase ->
lst[phase][depth]
}
}.toList()

output
}

val maxLookaheadDepth = (0..<period).map { phase ->
Expand Down Expand Up @@ -346,7 +346,22 @@ class CFind(
val lookaheadDepth = maxLookaheadDepth.map { minOf(lookaheadDepth, it) }

val successorLookaheadDepth = tempIndices.map { it[0].last() }.indexOf(0) + 1
val successorLookahead = this.lookaheadDepth.map {
// val successorLookahead = (0..<period).map { phase ->
// val lst = tempIndices.map { it[phase] }
// lst.map {
// val target = it[0] - indices[0][0]
// val known = setOf(0) //+ lookaheadIndices.subList(0, lookaheadDepth[phase]).map { it[phase][0] - indices[phase][0] }.toSet()
// for (i in lst) {
// if (i.indexOf(target) == i.size - 1 && lst[indexToRowMap[centralHeight] - 1] in known) {
// return@map
// }
// }

// -1
// }
// }

val successorLookahead = this.lookaheadDepth.map {
false && it > 0 && (successorLookaheadDepth == it + 1 || tempIndices[0][1].last() == 0)
}

Expand All @@ -367,7 +382,7 @@ class CFind(
val additionalDepthArray = IntArray(spacing) {
((rawAdditionalDepth - 1) + (offsets[(it + 1).mod(spacing)] - offsets[it])) / spacing + 1
}
val maxWidth: Int = widthsByHeight.slice(0 .. this.lookaheadDepth.max()).maxOf { it }
val maxWidth: Int = widthsByHeight.slice(0 .. minOf(this.lookaheadDepth.max(), widthsByHeight.size - 1)).maxOf { it }

// TODO fix approximate lookahead for spacing != 1
val approximateLookahead = this.lookaheadDepth.map {
Expand Down Expand Up @@ -1376,6 +1391,11 @@ class CFind(
val phase = depth.mod(period)
val originalPhase = if (originalPhase == -1) phase else originalPhase

// if (lookaheadDepth == 2) {
// println("phase $originalPhase")
// println(rows.map { "${it.depth} ${it.offset}" })
// }

// Encodes the neighbourhood with the central cell located at coordinate
fun encodeNeighbourhood(
coordinate: Coordinate,
Expand Down Expand Up @@ -1435,7 +1455,7 @@ class CFind(
var power = 0
bcNeighbourhood[memorisedBCsMap[bcCoordinate]!!].forEachIndexed { index, it ->
power = maxOf(power, pow(rule.numStates, index))
key += rows[it + bcCoordinate + coordinate, 0, row, depth] * pow(rule.numStates, index)
key += rows[it + bcCoordinate + coordinate, 0, row, depth, currentRow] * pow(rule.numStates, index)
}

// Adding current cell state & next cell state if needed
Expand Down Expand Up @@ -1562,8 +1582,9 @@ class CFind(
val approximateLookaheadRows: List<Row?>
val lookaheadDepthDiff = if (lookaheadDepth < this.lookaheadDepth[originalPhase]) {
approximateLookaheadRows = lookaheadRows[0]
if (lookaheadDepth >= 1) lookaheadIndices[lookaheadDepth - 1][phase].filter { it > 0 }.min()
else minIndices[phase]
if (lookaheadDepth >= 1) {
lookaheadIndices[lookaheadDepth - 1][originalPhase][0] - lookaheadIndices[lookaheadDepth][originalPhase][0]
} else indices[originalPhase][0] - lookaheadIndices[0][originalPhase][0]
} else {
approximateLookaheadRows = listOf()
0
Expand Down Expand Up @@ -1749,6 +1770,7 @@ class CFind(
// Telling algorithm which branches can be pruned and which branches can jump to the end
completedNode(node.predecessor!!)

// Checking the right boundary conditions if it has not already been done
if (
bcDepth != 1 && filteredRightBCs.isNotEmpty() &&
!checkBoundaryCondition(node, filteredRightBCs)
Expand All @@ -1757,13 +1779,18 @@ class CFind(
if (checkBoundaryCondition(node, filteredLeftBCs, offset=Coordinate(width * spacing - 1, 0))) {
// Running the lookahead
val row = Row(currentRow, node.completeRow!!, this)
row.depth = depth
if (lookaheadDepth < this.lookaheadDepth[originalPhase]) {
// Replaces the unknown rows within the lookahead with the current row value
val currentRowIndex = if (lookaheadDepth >= 1)
lookaheadIndices[lookaheadDepth - 1][originalPhase][0] - indices[0][0]
else indices[originalPhase][0] - indices[0][0]
val newRows = lookaheadRows.mapIndexed { index, rows ->
val temp = lookaheadIndices[lookaheadDepth][originalPhase].min() // TODO may not be legit
val tempIndices = lookaheadIndices[index + lookaheadDepth][originalPhase]
rows.mapIndexed { index, value -> if (tempIndices[index] == temp) row else value }
rows.mapIndexed { index, value -> if (tempIndices[index] == currentRowIndex) row else value }
}

// Runs the lookahead
val (lookaheadOutput, temp) = nextRow(
row,
newRows.first() as List<Row>,
Expand All @@ -1774,11 +1801,14 @@ class CFind(
originalPhase
)

// Removes the invalid memorised entries
if (approximateLookahead[originalPhase]) {
for (i in width - 1 ..< width + leftBC.size)
_lookaheadMemo2!![i] = -1
}

// Add the row to completed rows if lookahead succeeds,
// if not set the minimum depth where the lookahead failed
if (lookaheadOutput.isEmpty()) depthToCheck = temp
else completedRows.add(row)
} else {
Expand Down Expand Up @@ -1866,7 +1896,7 @@ class CFind(
if (indexToRowMap[coordinate.y] != -1) {
this[indexToRowMap[coordinate.y] - 1]?.get(coordinate.x) ?: -1
} else { // TODO optimise this
this[0]?.getPredecessor((coordinate.y - 1) * period)?.get(coordinate.x) ?: -1
mostRecentRow!!.getPredecessor(coordinate.y * period - 1)?.get(coordinate.x) ?: -1
}
} else if (generation == 1) {
// TODO optimise this
Expand Down
9 changes: 5 additions & 4 deletions src/jvmMain/kotlin/Main.jvm.kt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -88,13 +88,14 @@ actual fun main() {

println(R2VonNeumannINT(transitions).transitionString)

val ruletable = ruletableFromFile("SoManyShips3.rule")
//val ruletable = ruletableFromFile("SoManyShips3.rule")

// B2-ei3cjkr4cektyz5-cnr6-ik78/S01e2-ae3cnqry4cqrtwyz5-ain6ekn7e
// HROT("R2,C2,S6-11,B4,9-11,NW0020003330230320333000200")
val search = CFind(
HROT("R2,C2,S3,B0,NN"), 4, 1, 6, ShipSymmetry.ODD,
verbosity = 1, searchStrategy = SearchStrategy.PRIORITY_QUEUE, //lookaheadDepth = 0,
direction = Coordinate(1, 1)
HROT("R3,C2,S2,B3,N+"), 2, 1, 10, ShipSymmetry.ODD,
verbosity = 1, searchStrategy = SearchStrategy.PRIORITY_QUEUE, //lookaheadDepth = 2,
direction = Coordinate(1, 1), numThreads = 8
)
search.search()

Expand Down

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