From f0a20646ef3954e48c5012aa2425cd0d12b8f262 Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Fri, 14 Jul 2023 16:21:20 +0200
Subject: [PATCH] Type normalized-tbn?.

---
 scribblings/tbn.scrbl | 15 +++++++++++++++
 tbn.rkt               | 17 ++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/scribblings/tbn.scrbl b/scribblings/tbn.scrbl
index ed93a42..cfc3eb8 100644
--- a/scribblings/tbn.scrbl
+++ b/scribblings/tbn.scrbl
@@ -453,6 +453,21 @@ and pretty-prints the node labels.
               'b (tbf/state (hash 'a -1 'b 1) 1))))
 ]}
 
+@defproc[(normalized-tbn? [tbn TBN]) Boolean]{
+
+Checks whether @racket[tbn] is normalized: whether all of the
+functions have the same inputs, and whether these inputs are exactly
+the variables of @racket[tbn].
+
+@ex[
+(normalized-tbn?
+ (hash 'x (tbf/state (hash 'x 0 'y -1) -1)
+       'y (tbf/state (hash 'x -1 'y 0) -1)))
+(normalized-tbn?
+ (hash 'x (tbf/state (hash 'x 0 ) -1)
+       'y (tbf/state (hash 'y 0) -1)))
+]}
+
 @section{Miscellaneous utilities}
 
 @defproc[(group-truth-table-by-nai [tt (Listof (Listof Integer))])
diff --git a/tbn.rkt b/tbn.rkt
index 4348251..53d3a91 100644
--- a/tbn.rkt
+++ b/tbn.rkt
@@ -38,7 +38,7 @@
 
    TBN sbn? tbn->network
    parse-org-tbn read-org-tbn read-org-sbn
-   build-tbn-state-graph
+   build-tbn-state-graph normalized-tbn?
    )
 
   (: apply-tbf-to-state (-> TBF (State (U Zero One)) (U Zero One)))
@@ -514,6 +514,21 @@
                       (hash 'a (tbf/state (hash 'a -1 'b 1) 0)
                             'b (tbf/state (hash 'a -1 'b 1) 1))))
                     "digraph G {\n\tnode0 [label=\"a:0 b:0\"];\n\tnode1 [label=\"a:1 b:1\"];\n\tnode2 [label=\"a:0 b:1\"];\n\tnode3 [label=\"a:1 b:0\"];\n\tsubgraph U {\n\t\tedge [dir=none];\n\t\tnode0 -> node0 [];\n\t}\n\tsubgraph D {\n\t\tnode1 -> node0 [];\n\t\tnode2 -> node3 [];\n\t\tnode3 -> node0 [];\n\t}\n}\n")))
+
+  (: normalized-tbn? (-> TBN Boolean))
+  (define (normalized-tbn? tbn)
+    (define tbn-vars (hash-keys tbn))
+    (for/and ([tbf (in-list (hash-values tbn))])
+      (set=? tbn-vars (hash-keys (tbf/state-w tbf)))))
+
+  (module+ test
+    (test-case "normalized-tbn?"
+      (check-true (normalized-tbn?
+                   (hash 'x (tbf/state (hash 'x 0 'y -1) -1)
+                         'y (tbf/state (hash 'x -1 'y 0) -1))))
+      (check-false (normalized-tbn?
+                    (hash 'x (tbf/state (hash 'x 0 ) -1)
+                          'y (tbf/state (hash 'y 0) -1))))))
   )
 
 (module+ test