Create shorthand PolyMatrix.scalar() for .at(0,0)

1 files changed, 11 insertions, 0 deletions

diff --git a/polymatrix/polymatrix/mixins.py b/polymatrix/polymatrix/mixins.py
index 4cb89b3..f5cdb48 100644
--- a/polymatrix/polymatrix/mixins.py
+++ b/polymatrix/polymatrix/mixins.py
@@ -34,6 +34,17 @@ class PolyMatrixMixin(ABC):
             p.at(*entry) # if you have a MatrixIndex
         """
 
+    def scalar(self) -> PolyDict:
+        """
+        If the polymatrix is scalar, that is, a 1x1 matrix, this is a shorthand
+        for .at(0,0) for readability. Raises an error polymatrix is not scalar.
+        """
+        if self.shape != (1,1):
+            raise AttributeError("Use of .scalar() is not allowed because "
+                                 f"it has shape {self.shape}")
+
+        return self.at(0, 0)
+
     def entries(self) -> Iterable[tuple[MatrixIndex, PolyDict]]:
         """
         Iterate over the non-zero entries of the polynomial matrix.