Parellel Programming in Fortran with Coarrays

Thursday 6 May 2010, 6.00pm

The Davidson Building, 5 Southampton Street, London WC2 7HA. The nearest underground stations are Covent Garden and Charing Cross.

John Reid, JKR Associates and Rutherford Appleton Laboratory

The Fortran standard is currently under revision and is on schedule for final publication in the summer of this year. The technical content was decided late in 2008, so the new version will be known informally as Fortran 2008.

By far the biggest change from Fortran 2003 is the addition of coarrays.
A coarray program is replicated a fixed number of times, and each replication is called an image. The normal set of subscripts refers to memory addresses within an image while a second set of subscripts gives access to data in another image. Each image executes asynchronously with explicit synchronization provided by the programmer.

The aim of this talk is to introduce coarrays and explain why we believe that they will lead to easier development of parallel programs, faster execution times, and better maintainability. No detailed knowledge of Fortran will be assumed.

Free, but to gain admission please email your name to our Membership Secretary, Dr Frank Martin at

View the slides for this event (PDF - 29 KB)