Initial commit

tools/adj2dot

@@ -0,0 +1,54 @@
+#!/usr/bin/python3
+
+# SPDX-FileCopyrightText: 2025 Ämin Baumeler <amin@indyfac.ch>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+import sys
+import numpy as np
+
+if len(sys.argv) != 1:
+    print(
+        sys.argv[0]
+        + """
+
+Read adjacency vector of a digraph from stdin, and transform it to
+the GraphViz dot language for graph visualization.
+
+The input represents the adjacency vector of a digraph. A 1 in
+position (i,j) of a line is an arc i<-j, and a 0 no arc i<-j.
+The coordinate i runs from 0 to n-1, the corrdinate j likewise, but
+with j != i. The entries are ordered lexicographically."""
+    )
+    sys.exit(1)
+
+
+def print_dot(n, adj, labels):
+    print('strict digraph "DG" {')
+    for v in range(n):
+        print(f'GN{v} [label="{labels[v]}"];')
+    i = 0
+    j = 1
+    for entry in adj:
+        if entry:
+            print(f"GN{j} -> GN{i}")
+        j = j + 1
+        if i == j:
+            j = j + 1
+        if j >= n:
+            i = i + 1
+            j = 0
+    print("}")
+
+
+for line in sys.stdin:
+    labels = None
+    if ":" in line:
+        labels, line = line.split(":")
+        labels = tuple(map(int, tuple(labels)))
+    adj = tuple(map(int, tuple(line.strip())))
+    n = int(np.ceil(np.sqrt(len(adj))))
+    if not labels:
+        labels = tuple(range(n))
+    print_dot(n, adj, labels)
+    sys.exit(0)