Fixed incorrect sign convention

src/build_system_wsmp.f90

@@ -194,9 +194,9 @@ do ileaves=1,osolve%nleaves
                       iloc=ifind_loc_wsmp(i1loc,i1,ja,ia,n_iproc,nz_loc)
                       elem_dz=(osolve%icon(5,ileaves)-osolve%icon(1,ileaves))*params%vex
                       if (k1 < 5) then                        
-                        avals(iloc)=avals(iloc)+(params%dt*weightel(ileaves))/(2*elem_dz)
-                      else
                         avals(iloc)=avals(iloc)-(params%dt*weightel(ileaves))/(2*elem_dz)
+                      else
+                        avals(iloc)=avals(iloc)+(params%dt*weightel(ileaves))/(2*elem_dz)
                       endif
                     endif
                   endif