[HA-7.0] Add initial sollution for 7th task

project/task7.py

@@ -0,0 +1,48 @@
+from scipy.sparse import lil_matrix
+from pyformlang.cfg import CFG, Terminal
+import networkx as nx
+from typing import Set, Tuple
+from project.task6 import cfg_to_weak_normal_form
+
+
+def cfpq_with_matrix(cfg, graph, start_nodes=None, final_nodes=None):
+    wnf = cfg_to_weak_normal_form(cfg)
+    mapVarIndex = {
+        variable: index
+        for index, variable in enumerate(
+            {production.head for production in wnf.productions}
+        )
+    }
+
+    matrices = {}
+    n = graph.number_of_nodes()
+    for production in wnf.productions:
+        matrices[production.head] = lil_matrix((n, n), dtype=bool)
+        if len(production.body) == 1 and isinstance(production.body[0], Terminal):
+            for start, end, label in graph.edges.data("label"):
+                if str(production.body[0]) == str(label):
+                    matrices[production.head][start, end] = True
+
+    changed = True
+    while changed:
+        changed = False
+        for production in wnf.productions:
+            if (
+                len(production.body) == 2
+                and production.body[0] in mapVarIndex
+                and production.body[1] in mapVarIndex
+            ):
+                prev = matrices[production.head].nnz
+                matrices[production.head] += (
+                    matrices[production.body[0]] * matrices[production.body[1]]
+                )
+                changed = changed or (prev != matrices[production.head].nnz)
+
+    return {
+        (row, column)
+        for variable, matrix in matrices.items()
+        for row, column in zip(matrix.tocoo().row, matrix.tocoo().col)
+        if variable == wnf.start_symbol
+        and (start_nodes is None or row in start_nodes)
+        and (final_nodes is None or column in final_nodes)
+    }