Fix bug introduced by backwards compatibility code

Bug was introduced by 21e75589a5700bf8215ce87826c4e9daac7c4071

1 files changed, 14 insertions, 12 deletions

diff --git a/polymatrix/polymatrix/init.py b/polymatrix/polymatrix/init.py
index f9a3de1..a2d28f2 100644
--- a/polymatrix/polymatrix/init.py
+++ b/polymatrix/polymatrix/init.py
@@ -20,14 +20,15 @@ def init_poly_matrix(
 ):
     # This is here because the old code in expression.mixins usually gives raw dictionaries
     if not isinstance(data, PolyMatrixDict):
-        data = PolyMatrixDict({
-            MatrixIndex(*entry): PolyDict({
-                MonomialIndex(VariableIndex(*v) for v in monomial): coeff
-            })
-            for entry, poly in data.items()
-                for monomial, coeff in poly.items()
-        })
-    
+        wrapped = PolyMatrixDict.empty()
+        for entry, poly in data.items():
+            p = PolyDict.empty()
+            for monomial, coeff in poly.items():
+                idx = MonomialIndex(VariableIndex(*v) for v in monomial)
+                p[idx] = coeff
+            wrapped[*entry] = p
+        data = wrapped
+
     return PolyMatrixImpl(
         data=data,
         shape=shape,
@@ -40,10 +41,11 @@ def init_broadcast_poly_matrix(
 ) -> BroadcastPolyMatrixMixin:
     # This is here because the old code in expression.mixins usually gives raw dictionaries
     if not isinstance(data, PolyDict):
-        data = PolyDict({
-            MonomialIndex(VariableIndex(*v) for v in monomial): coeff
-            for monomial, coeff in data.items()
-        })
+        p = PolyDict.empty()
+        for monomial, coeff in data.items():
+            idx = MonomialIndex(VariableIndex(*v) for v in monomial)
+            p[idx] = coeff
+        data = p
 
     return BroadcastPolyMatrixImpl(
         data=data,