Make stub for determinant

1 files changed, 46 insertions, 0 deletions

diff --git a/mdpoly/operations/determinant.py b/mdpoly/operations/determinant.py
new file mode 100644
index 0000000..63aaf20
--- /dev/null
+++ b/mdpoly/operations/determinant.py
@@ -0,0 +1,46 @@
+from __future__ import annotations
+from typing import TYPE_CHECKING
+
+from typing import Type
+from dataclassabc import dataclassabc
+
+from ..abc import ReprT
+from ..index import Shape
+from ..errors import AlgebraicError
+
+from . import UnaryOp
+
+if TYPE_CHECKING:
+    from ..abc import ReprT
+    from ..state import State
+
+
+@dataclassabc(eq=False)
+class Det(UnaryOp): 
+    """ Compute the determinant of a matrix. """
+
+    @property
+    def shape(self) -> Shape:
+        if not self.inner.shape.cols == self.inner.shape.rows:
+            raise AlgebraicError("Cannot take determinant of non-square matrix "
+                                 f"{str(self)} (shape {self.inner.shape}).")
+
+        return Shape.scalar()
+
+    def to_repr(self, repr_type: Type[ReprT], state: State) -> tuple[ReprT, State]:
+        """ See :py:meth:`mdpoly.abc.Expr.to_repr`. """
+        # Make a new empty representation
+        r = repr_type(self.shape)
+
+        # Compute LU decomposition by Doolittle's method
+        lower = repr_type(self.inner.shape)
+        upper = repr_type(self.upper.shape)
+
+        for i in range(self.inner.shape.rows):
+            raise NotImplementedError
+
+        return r, state
+
+    
+    def __str__(self):
+        return "(det {self.inner})"