diff --git a/src/sand-wedge.cc b/src/sand-wedge.cc
index 7690a6b5a80f8c176e18b691aff7399a56a0c112..62890d3ffd5a675dc361e529cc398da5e33122b4 100644
--- a/src/sand-wedge.cc
+++ b/src/sand-wedge.cc
@@ -404,7 +404,7 @@ int main(int argc, char *argv[]) {
     Vector a_initial(leafVertexCount);
     a_initial = 0.0;
     {
-      // We solve Ma = ell0 - [Au + Cv + Psi(v)]
+      // We solve Ma = ell0 - [Au + Cv + DPsi(v)]
       Vector accelerationRHS(leafVertexCount);
       {
         accelerationRHS = 0.0;