LGS-164 belief propagation for polytrees, special case of OR cpds, refactored from LGSv0.0.2

1 files changed, 19 insertions, 0 deletions

diff --git a/beliefs/utils/math_helper.py b/beliefs/utils/math_helper.py
new file mode 100644
index 0000000..a25ea68
--- /dev/null
+++ b/beliefs/utils/math_helper.py
@@ -0,0 +1,19 @@
+"""Random math utils."""
+
+
+def is_kronecker_delta(vector):
+    """Returns True if vector is a kronecker delta vector, False otherwise.
+    Specific evidence ('YES' or 'NO') is a kronecker delta vector, whereas
+    virtual evidence ('MAYBE') is not.
+    """
+    count = 0
+    for x in vector:
+        if x == 1:
+            count += 1
+        elif x != 0:
+            return False
+
+    if count == 1:
+        return True
+    else:
+        return False