Fixed some OpenACC directives (#859)

Author: prathi-wind

src/common/m_finite_differences.fpp

@@ -15,8 +15,7 @@ contains
         integer :: x, y, z !< Generic loop iterators
 
         real(wp) :: divergence
-
-        !$acc parallel loop collapse(3) private(divergence)
+        !$acc parallel loop collapse(3) gang vector default(present) private(divergence)
         do x = ix_s%beg, ix_s%end
             do y = iy_s%beg, iy_s%end
                 do z = iz_s%beg, iz_s%end

src/simulation/m_hypoelastic.fpp

@@ -399,7 +399,7 @@ contains
 
         if (n == 0) then
             l = 0; q = 0
-            !$acc parallel loop collapse(1) gang vector default(present)
+            !$acc parallel loop gang vector default(present)
             do k = 0, m
                 rhs_vf(damage_idx)%sf(k, l, q) = (alpha_bar*max(abs(q_cons_vf(stress_idx%beg)%sf(k, l, q)) - tau_star, 0._wp))**cont_damage_s
             end do

src/simulation/m_surface_tension.fpp

@@ -336,7 +336,7 @@ contains
         !$acc update device(is1, is2, is3, iv)
 
         if (recon_dir == 1) then
-            !$acc parallel loop collapse(4) default(present)
+            !$acc parallel loop collapse(4) gang vector default(present)
             do i = iv%beg, iv%end
                 do l = is3%beg, is3%end
                     do k = is2%beg, is2%end
@@ -349,7 +349,7 @@ contains
             end do
             !$acc end parallel loop
         else if (recon_dir == 2) then
-            !$acc parallel loop collapse(4) default(present)
+            !$acc parallel loop collapse(4) gang vector default(present)
             do i = iv%beg, iv%end
                 do l = is3%beg, is3%end
                     do k = is2%beg, is2%end
@@ -362,7 +362,7 @@ contains
             end do
             !$acc end parallel loop
         else if (recon_dir == 3) then
-            !$acc parallel loop collapse(4) default(present)
+            !$acc parallel loop collapse(4) gang vector default(present)
             do i = iv%beg, iv%end
                 do l = is3%beg, is3%end
                     do k = is2%beg, is2%end

src/simulation/m_viscous.fpp

@@ -1329,7 +1329,7 @@ contains
         end do
 
         if (n > 0) then
-            !$acc parallel loop collapse(3) gang vector
+            !$acc parallel loop collapse(3) gang vector default(present)
             do l = is3_viscous%beg, is3_viscous%end
                 do k = is2_viscous%beg, is2_viscous%end
                     do j = is1_viscous%beg, is1_viscous%end
@@ -1342,7 +1342,7 @@ contains
         end if
 
         if (p > 0) then
-            !$acc parallel loop collapse(3) gang vector
+            !$acc parallel loop collapse(3) gang vector default(present)
             do l = is3_viscous%beg, is3_viscous%end
                 do k = is2_viscous%beg, is2_viscous%end
                     do j = is1_viscous%beg, is1_viscous%end

src/simulation/m_weno.fpp

@@ -673,7 +673,7 @@ contains
 
         if (weno_order == 1) then
             if (weno_dir == 1) then
-                !$acc parallel loop collapse(4) default(present)
+                !$acc parallel loop collapse(4) gang vector default(present)
                 do i = 1, ubound(v_vf, 1)
                     do l = is3_weno%beg, is3_weno%end
                         do k = is2_weno%beg, is2_weno%end
@@ -686,7 +686,7 @@ contains
                 end do
                 !$acc end parallel loop
             else if (weno_dir == 2) then
-                !$acc parallel loop collapse(4) default(present)
+                !$acc parallel loop collapse(4) gang vector default(present)
                 do i = 1, ubound(v_vf, 1)
                     do l = is3_weno%beg, is3_weno%end
                         do k = is2_weno%beg, is2_weno%end
@@ -699,7 +699,7 @@ contains
                 end do
                 !$acc end parallel loop
             else if (weno_dir == 3) then
-                !$acc parallel loop collapse(4) default(present)
+                !$acc parallel loop collapse(4) gang vector default(present)
                 do i = 1, ubound(v_vf, 1)
                     do l = is3_weno%beg, is3_weno%end
                         do k = is2_weno%beg, is2_weno%end