 
 
     /* ------------------------ Transverse Propagation : X-faces ---------------------- */
+
+    ifaces_x = mx + 1;            /* Match edges visited by Clawpack */
+    ifaces_y = my + 2;
+    num_ifaces = ifaces_x*ifaces_y;
 
 
     /*     transverse-x

    
    */              

    ifaces_x = mx + 1;  /* Visit x - edges of all non-ghost cells */
    ifaces_y = my + 2;
    num_ifaces = ifaces_x*ifaces_y;

    for(thread_index = threadIdx.x; thread_index < num_ifaces; thread_index += blockDim.x)
    { 
        ix = thread_index % ifaces_x;

            gp[I_q - 1] -= gupdate;   
        }            
    }
    //__syncthreads();


    /*     transverse-x
