                 for(mq = 0; mq < meqn; mq++)
                 {
                     I_q = I + mq*zs;
-                    cqyy = fabs(s[mw])*(1.0 - fabs(s[mw])*dtdy)*wave[mq];
+                    cqyy = abs(s[mw])*(1.0 - abs(s[mw])*dtdy)*wave[mq];
 
                     gm[I_q] += 0.5*cqyy;   
                     gp[I_q] += 0.5*cqyy;  

            gp[I_q - 1] -= gupdate;   
        }            

        //__syncthreads();

        for(mq = 0; mq < meqn; mq++)
        {

            gp[I_q + ys] -= gupdate;
        }
        
        __threadfence_block();
         
    } 

    /* May not the synchthreads(), below, since gm/gp updated above, but only fm/gp
       updated below */
    //__syncthreads();  

    
    /* ----------------------------- Transverse : Y-faces ----------------------------- */


