To: J3 10-112r1 From: John Reid Subject: Comment GB-12: Difference between SYNC IMAGES and SYNC ALL Date: 2010 February 15 References: WG5/N1802, WG5/N1803, J3/09-007r3 DISCUSSION The difference between SYNC IMAGES and SYNC ALL should be clarified. EDIT [190:15+]In 8.5.4 "SYNC IMAGES statement" at the end of Note 8.37, add "When the following example runs on five or more images, each image synchronizes with both of its neighbors, in a circular fashion. INTEGER :: up, down IF (NUM_IMAGES()>1) THEN up = THIS_IMAGE()+1; IF (up>NUM_IMAGES()) up = 1 down = THIS_IMAGE()-1; IF (down==0) down = NUM_IMAGES() SYNC IMAGES ( (/ up, down /) ) END IF This might appear to have the same effect as SYNC ALL but there is no ordering between the preceding and succeeding segments on non-adjacent images. For example, the segment preceding the SYNC IMAGES statement on image 3 will be ordered before those succeeding it on images 2 and 4, but not those on images 1 and 5."