implement PCFG scoring

src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/CFG.kt

@@ -256,7 +256,7 @@ class BiMap(cfg: CFG) {
 
 // n.b., this only works if the CFG is acyclic, i.e., finite otherwise it will loop forever
 fun CFG.toPTree(from: Σᐩ = START_SYMBOL): PTree =
-  PTree(from, bimap[from].map { toPTree(it[0]) to if(it.size == 1) PTree() else toPTree(it[1]) })
+  PTree(from, bimap[from].map { toPTree(it[0]) to if (it.size == 1) PTree() else toPTree(it[1]) })
 
 /*
 Γ ⊢ ∀ v.[α→*]∈G ⇒ α→[β]       "If all productions rooted at α

src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/SeqValiant.kt

@@ -121,7 +121,7 @@ class PTree(val root: String = ".ε", val branches: List<Π2A<PTree>> = listOf()
     }
 
   fun sampleStrWithPCFG(pcfgTable: Map<Π3A<Σᐩ>, Int>): Sequence<String> =
-    sequence { while (true) yield(samplePCFG(pcfgTable)) }
+    sequence { while (true) yield(samplePCFG3(pcfgTable)) }
 
   // Samples instantaneously from the parse forest, but may return duplicates
   // and only returns a fraction of the number of distinct strings when compared
@@ -149,15 +149,28 @@ class PTree(val root: String = ".ε", val branches: List<Π2A<PTree>> = listOf()
   fun Σᐩ.name() = if ("~" in this) split("~")[1] else this
   val triples by lazy { branches.map { root.name() to it.first.root.name() to it.second.root.name() } }
 
-  fun samplePCFG(pcfgTable: Map<Π3A<Σᐩ>, Int>): Σᐩ {
+  fun samplePCFG5(pcfgTable: Map<Π5A<Σᐩ>, Int>, root: Σᐩ = "NIL", upLeft: Σᐩ = "NIL", upRight: Σᐩ = "NIL"): Σᐩ {
+    if (branches.isEmpty()) return if ("ε" in root) "" else root
+    val rt = root.name()
+    val probs = triples.map { (pcfgTable[rt to upLeft to upRight to it.second to it.third] ?: 1) + 1 }
+    val cdf = probs.runningReduce { acc, i -> acc + i }
+    val rnd = Random.nextInt(probs.sum())
+    val childIdx = cdf.binarySearch { it.compareTo(rnd) }.let { if (it < 0) -it - 1 else it }
+    val (l, r) = branches[childIdx]
+    val (lr, rr) = l.root.name() to r.root.name()
+    val (a, b) = l.samplePCFG5(pcfgTable, rt, lr, rr) to r.samplePCFG5(pcfgTable, rt, lr, rr)
+    return if (a.isEmpty()) b else if (b.isEmpty()) a else "$a $b"
+  }
+
+  fun samplePCFG3(pcfgTable: Map<Π3A<Σᐩ>, Int>): Σᐩ {
     if (branches.isEmpty()) return if ("ε" in root) "" else root
 
     val probs = triples.map { (pcfgTable[it] ?: 1) + 1 }
     val cdf = probs.runningReduce { acc, i -> acc + i }
     val rnd = Random.nextInt(probs.sum())
     val childIdx = cdf.binarySearch { it.compareTo(rnd) }.let { if (it < 0) -it - 1 else it }
     val (l, r) = branches[childIdx]
-    val (a, b) = l.samplePCFG(pcfgTable) to r.samplePCFG(pcfgTable)
+    val (a, b) = l.samplePCFG3(pcfgTable) to r.samplePCFG3(pcfgTable)
     return if (a.isEmpty()) b else if (b.isEmpty()) a else "$a $b"
   }
 

src/commonMain/kotlin/ai/hypergraph/kaliningraph/parsing/Tree.kt

@@ -3,7 +3,7 @@ package ai.hypergraph.kaliningraph.parsing
 import ai.hypergraph.kaliningraph.graphs.LGVertex
 import ai.hypergraph.kaliningraph.graphs.LabeledGraph
 import ai.hypergraph.kaliningraph.tensor.FreeMatrix
-import ai.hypergraph.kaliningraph.types.Π3A
+import ai.hypergraph.kaliningraph.types.*
 
 typealias TreeMatrix = FreeMatrix<Forest>
 typealias Forest = Set<Tree>
@@ -33,6 +33,17 @@ class Tree constructor(
     else listOf(Π3A(root, children[0].root, children[1].root)) +
       children.flatMap { it.triples() }
 
+  fun quintuples(parent: String = "NIL", lsibling: String = "NIL", rsibling: String = "NIL"): List<Π5A<Σᐩ>> =
+    if (children.size != 2) listOf()
+    else listOf(Π5A(parent, lsibling, rsibling, children[0].root, children[1].root)) +
+      children[0].quintuples(root, children[0].root, children[1].root) +
+      children[1].quintuples(root, children[0].root, children[1].root)
+
+  fun logProb(pcfgMap: Map<Π3A<Σᐩ>, Int>): Double =
+    if (children.isEmpty()) 0.0
+    else (pcfgMap[root to children[0].root to children[1].root]?.toDouble() ?: 0.0) +
+      children.sumOf { it.logProb(pcfgMap) }
+
   fun toGraph(j: Σᐩ = "0"): LabeledGraph =
     LabeledGraph { LGVertex(root, "$root.$j").let { it - it } } +
       children.foldIndexed(

src/commonMain/kotlin/ai/hypergraph/kaliningraph/types/Arrays.kt

@@ -8,6 +8,7 @@ import kotlin.jvm.JvmName
 typealias Π2A<A> = Π2<A, A>
 typealias Π3A<A> = Π3<A, A, A>
 typealias Π4A<A> = Π4<A, A, A, A>
+typealias Π5A<A> = Π5<A, A, A, A, A>
 
 // Multimorphic arrays
 data class Π1<A>(val π1: A)/*: V1<A> by VT(π1)*/