diff --git a/matrices.py b/matrices.py
index 01093da..672f64e 100644
--- a/matrices.py
+++ b/matrices.py
@@ -3,10 +3,13 @@
 import scipy.sparse as sparse
 
 
-def constructC(dxOpTemp, rhsDxOpTemp, dyOpTemp, rhsDyOpTemp, psi, dxOpPsi, dyOpPsi, sqrtRa):
+def constructC(dxOpTemp, rhsDxOpTemp, dyOpTemp, rhsDyOpTemp, dlOpTemp, rhsDlOpTemp, psi, dxOpPsi, dyOpPsi, sqrtRa):
 
-    rhs = sqrtRa * (rhsDxOpTemp * (dyOpPsi * psi) - rhsDyOpTemp * (dxOpPsi * psi))
+    dxPsi = sparse.diags((dxOpPsi @ psi)[:, 0], 0)
+    dyPsi = sparse.diags((dyOpPsi @ psi)[:, 0], 0)
 
-    return sqrtRa * (
-            sparse.diags([(dxOpTemp * dyOpPsi * psi)[:, 0]], [0]) - sparse.diags([(dxOpPsi * psi)[:, 0]], [0])), rhs
-    # return 0
+    C = sqrtRa * (dyPsi @ dxOpTemp - dxPsi @ dyOpTemp ) - dlOpTemp
+
+    rhsC = - rhsDlOpTemp + sqrtRa * (dyPsi @ rhsDxOpTemp- dyPsi @ rhsDyOpTemp)
+
+    return C,rhsC