1 files changed, 81 insertions, 0 deletions
diff --git a/polymatrix/expression/mixins/divisionexprmixin.py b/polymatrix/expression/mixins/divisionexprmixin.py
new file mode 100644
index 0000000..01d3505
--- /dev/null
+++ b/polymatrix/expression/mixins/divisionexprmixin.py
@@ -0,0 +1,81 @@
+
+import abc
+import dataclasses
+
+from polymatrix.expression.init.initpolymatrix import init_poly_matrix
+from polymatrix.expression.mixins.expressionbasemixin import ExpressionBaseMixin
+from polymatrix.expression.polymatrix import PolyMatrix
+from polymatrix.polymatrixexprstate import PolyMatrixExprState
+
+
+class DivisionExprMixin(ExpressionBaseMixin):
+    @property
+    @abc.abstractmethod
+    def left(self) -> ExpressionBaseMixin:
+        ...
+
+    @property
+    @abc.abstractmethod
+    def right(self) -> ExpressionBaseMixin:
+        ...
+
+    # overwrites abstract method of `ExpressionBaseMixin`
+    @property
+    def shape(self) -> tuple[int, int]:
+        return self.left.shape
+
+    # overwrites abstract method of `ExpressionBaseMixin`
+    def apply(
+        self, 
+        state: PolyMatrixExprState,
+    ) -> tuple[PolyMatrixExprState, PolyMatrix]:
+        if self in state.cached_polymatrix:
+            return state, state.cached_polymatrix[self]
+
+        state, left = self.left.apply(state=state)
+        state, right = self.right.apply(state=state)
+
+        assert right.shape == (1, 1)
+
+        terms = {}
+
+        division_variable = state.n_param
+        state = state.register(n_param=1)
+
+        for row in range(self.shape[0]):
+            for col in range(self.shape[1]):
+
+                try:
+                    underlying_terms = left.get_poly(row, col)
+                except KeyError:
+                    continue
+
+                def gen_monomial_terms():
+                    for monomial, value in underlying_terms.items():
+                        yield monomial + (division_variable,), value
+
+                terms[row, col] = dict(gen_monomial_terms())
+
+        def gen_auxillary_terms():
+            for monomial, value in right.get_poly(0, 0).items():
+                yield monomial + (division_variable,), value
+
+        auxillary_terms = dict(gen_auxillary_terms())
+
+        if tuple() not in auxillary_terms:
+            auxillary_terms[tuple()] = 0
+
+        auxillary_terms[tuple()] -= 1
+
+        poly_matrix = init_poly_matrix(
+            terms=terms,
+            shape=self.shape,
+        )
+
+        state = dataclasses.replace(
+            state, 
+            auxillary_terms=state.auxillary_terms + (auxillary_terms,),
+            cached_polymatrix=state.cached_polymatrix | {self: poly_matrix},
+        )
+
+        return state, poly_matrix