diff --git a/tensorproductmultigrid_Source/communication.f90 b/tensorproductmultigrid_Source/communication.f90
index e549f3a09d21faab81d37bbb1528b71a946dbe67..2cbb3ee82aaa751e0a5d2c4c8fcd7546bbffb062 100644
--- a/tensorproductmultigrid_Source/communication.f90
+++ b/tensorproductmultigrid_Source/communication.f90
@@ -478,8 +478,8 @@ contains
         if (LUseT) then
            local_sumt = 0.0_rl
            do iz=0,nz+1
-              do iy=a%iy_min,a%iy_max
-                 do ix=a%ix_min,a%ix_max
+              do iy=a%icompy_min,a%icompy_max
+                 do ix=a%icompx_min,a%icompx_max
                     local_sumt = local_sumt &
                          + a%st(ix,iy,iz)*b%st(ix,iy,iz)
                  end do