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Thread-Topic: are race conditions allowed in do concurrent? 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boundary="_000_DM6PR12MB31302BD1D034319D5CD42B7ACBF1ADM6PR12MB3130namp_" MIME-Version: 1.0 X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3130.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5e4ce280-76a7-47db-c2ae-08dbb39ea6c9 X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Sep 2023 14:43:38.7416 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 1f98dj6GR45E48noXHXdVSOMlM6dnnmPCepIBQUOKQY78VBmmrcZkHlATG3Cvno2r2WFsXCfDkd2eLbGrjpWcA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB7888 Sender: owner-sc22wg5@open-std.org Precedence: bulk --_000_DM6PR12MB31302BD1D034319D5CD42B7ACBF1ADM6PR12MB3130namp_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Is this a legal program in Fortran with defined behavior? If it is illegal= or the behavior is undefined, where do we say that? program main integer :: k real :: x x =3D 0.0 do concurrent (k=3D1:2) shared(x) x =3D real(k) end do print*,x end program main Is that what the following is intended to do? =93If a variable has SHARED locality, appearances of the variable within th= e DO CONCURRENT construct refer to the variable in the innermost executable= construct or scoping unit that includes the DO CONCURRENT construct. If it= is defined or becomes undefined during any iteration, it shall not be refe= renced, defined, or become undefined during any other iteration.=94 If so, then I am struggling to apply this to arrays. When we say a variabl= e has shared locality, is the variable the array or the element? We can on= ly put array names in SHARED(), but applying the text regarding =93to becom= e defined=94 from the perspective of arrays appears to have interesting con= sequences. Thanks, Jeff --_000_DM6PR12MB31302BD1D034319D5CD42B7ACBF1ADM6PR12MB3130namp_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

Is this a legal pro= gram in Fortran with defined behavior?  If it is illegal or the behavi= or is undefined, where do we say that?

 

program main

  integer :: k=

  real :: x

  x =3D 0.0

  do concurren= t (k=3D1:2) shared(x)

    = x =3D real(k)

  end do<= /o:p>

  print*,x

end program main

 

Is t= hat what the following is intended to do?

 

=93If a variable ha= s SHARED locality, appearances of the variable within the DO CONCURRENT con= struct refer to the variable in the innermost executable construct or scopi= ng unit that includes the DO CONCURRENT construct. If it is defined or becomes undefined during any iteration, it = shall not be referenced, defined, or become undefined during any other iter= ation.=94=

 

If s= o, then I am struggling to apply this to arrays.  When we say a variab= le has shared locality, is the variable the array or the element?  We = can only put array names in SHARED(), but applying the text regarding =93to become defined=94 from the perspective of arrays = appears to have interesting consequences.

 

Thanks,<= /span>


Jeff

 

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