To: J3                                                   08-219r1
From: Bill Long
Subject: Reply to Comment J32005
Date: 12 Aug 2008
References: J3/08-007r2 (WG5/N1723)

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Comment from Robert Corbett:

The Fortran 2008 draft should not be approved unless coarrays
are made optional.

Coarrays are too new to belong in Fortran 2008.  Many models
for parallel programming have been developed.  Coarrays are
not clearly superior to these other models.  Making coarrays
optional would allow further development of coarrays without
creating problems if other models of parallel programming
prove more successful.

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J3 response:

Coarrays have been implemented in commercially available compilers for
a decade, which is longer that the typical lifetime of a Fortran
standard. The SPMD programming model implemented in Fortran with
coarrays is that used by MPI, which is the most successful parallel
programming model available. Previous experience with optional parts
of the standard is that they are not widely implemented. Since the
most often voiced complaint about coarrays is that they are not widely
available, this is not an appropriate course of action. The status of
coarrays in the proposed Fortran standard has been extensively debated
and balloted, and we feel the outcome should not be changed.