Changeset 4233 for palm

Timestamp:

Sep 20, 2019 9:55:54 AM (5 years ago)

Author:

knoop

Message:

OpenACC support added to global_min_max.f90

Location:

palm/trunk/SOURCE

Files:

• global_min_max.f90 (modified) (4 diffs)
• timestep.f90 (modified) (2 diffs)

palm/trunk/SOURCE/global_min_max.f90

@@ -25 +25 @@
 ! -----------------
 ! $Id$
+! OpenACC support added
+! 
+! 4182 2019-08-22 15:20:23Z scharf
 ! Corrected "Former revisions" section
 ! 
@@ -89 +92 @@
     REAL(wp) ::  fmin_l(2)  !<
 #endif
+#if defined( _OPENACC )
+    REAL(wp)     ::  red        !< scalar for reduction with OpenACC
+    INTEGER(iwp) ::  count_eq   !< counter for locations of maximum
+#endif
     REAL(wp), OPTIONAL ::  value1  !<
 
@@ -177 +184 @@
 !-- Determine absolute array maximum
     IF ( mode == 'abs' )  THEN
+
+#if defined( _OPENACC )
+       red = 0.0_wp
+       !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) &
+       !$ACC PRESENT(ar) COPY(red) REDUCTION(MAX: red)
+       DO  k = k1, k2
+          DO  j = j1, j2
+             DO  i = i1, i2
+                IF ( ABS( ar(i,j,k) ) > red )  THEN
+                   red = ABS( ar(i,j,k) )
+                ENDIF
+             ENDDO
+          ENDDO
+       ENDDO
+       fmax_l(1) = red
+
+!
+!--    Determine the maximum's position and count how often it is found.
+       count_eq = 0
+       !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) &
+       !$ACC PRESENT(ar) COPY(fmax_ijk_l(1:3), count_eq) &
+       !$ACC REDUCTION(+:count_eq)
+       DO  k = k1, k2
+          DO  j = j1, j2
+             DO  i = i1, i2
+                IF ( ABS( ar(i,j,k) ) == red )  THEN
+                   fmax_ijk_l(1) = i
+                   fmax_ijk_l(2) = j
+                   fmax_ijk_l(3) = k
+                   count_eq = count_eq + 1
+                ENDIF
+             ENDDO
+          ENDDO
+       ENDDO
+
+       IF ( count_eq == 1 ) THEN
+!
+!--       We found a single maximum element and correctly got its position. Transfer its
+!--       value to handle the negative case correctly.
+          !$ACC UPDATE HOST(ar(fmax_ijk_l(1):fmax_ijk_l(1),fmax_ijk_l(2),fmax_ijk_l(3)))
+       ELSE
+!
+!--       We found no maximum element (?) or multiple, so the position is not correct.
+!--       Copy the full array to the host and determine the maximum sequentially...
+          !$ACC UPDATE HOST(ar(i1:i2,j1:j2,k1:k2))
+#endif
 
 !
@@ -197 +250 @@
        ENDDO
 
+#if defined( _OPENACC )
+!
+!--       Close ELSE case from above
+       ENDIF
+#endif
+
 !
 !--    Set a flag in case that the determined value is negative.

palm/trunk/SOURCE/timestep.f90

@@ -25 +25 @@
 ! -----------------
 ! $Id$
+! OpenACC data update host removed
+! 
+! 4182 2019-08-22 15:20:23Z scharf
 ! Corrected "Former revisions" section
 ! 
@@ -119 +122 @@
     CALL cpu_log( log_point(12), 'calculate_timestep', 'start' )
 
-    !$ACC UPDATE &
-    !$ACC HOST(u(nzb:nzt+1,nysg:nyng,nxlg:nxrg)) &
-    !$ACC HOST(v(nzb:nzt+1,nysg:nyng,nxlg:nxrg)) &
-    !$ACC HOST(w(nzb:nzt+1,nysg:nyng,nxlg:nxrg)) &
-    !$ACC HOST(kh(nzb:nzt+1,nysg:nyng,nxlg:nxrg)) &
-    !$ACC HOST(km(nzb:nzt+1,nysg:nyng,nxlg:nxrg))
-
 !
 !-- In case of Galilei-transform not using the geostrophic wind as translation