Good grins. Thanks Paul. Larry Baker US Geological Survey 650-329-5608 ba...@usgs.gov
On 20 Feb 2015, at 11:49 AM, Paul Hargrove wrote: > > INTEGER JEFF(3) > DATA JEFF/4HMR. ,4HFORT,3HRAN/ > > If you can understand that, you should probably pretend you can't :-) > > -Paul [who has actually used Computed GO TO and Arithmetic IF] > > On Fri, Feb 20, 2015 at 11:28 AM, Larry Baker <ba...@usgs.gov> wrote: > Excellent, Mr. Fortran. Thank you. > > By the way, I meant to write Branch ON Low Bit Set/Clear. > > Larry Baker > US Geological Survey > 650-329-5608 > ba...@usgs.gov > > > > On 20 Feb 2015, at 11:22 AM, Jeff Squyres (jsquyres) wrote: > >> On Feb 20, 2015, at 2:12 PM, Larry Baker <ba...@usgs.gov> wrote: >>> >>> Beware, this has/may not always be the case. This is due to C's historical >>> confusion/misuse of integers as boolean data types. On VAX hardware, the >>> low bit was the only significant part of a Fortran LOGICAL data type, owing >>> to the architectural support (Branch of Low Bit Set/Clear) for the low bit >>> in a status word meaning success/failure. I doubt anyone uses VAXes and >>> MPI, so this is not likely to cause users problems. >> >> Note that this comment was referring to two things: >> >> 1. 0/1 array index issues >> 2. .true./.false. issues >> >> We actually check for the value of .true. in configure, and use that >> everywhere. I believe this particular portion of the code simply looks for >> .false.==(C int)0, and .true. is anything else. That was deemed good enough >> because this portion of the code is simply *checking* for true/false. Where >> we *assign* true/false in the Fortran boolean sense, we use the value >> determined by configure. >> >> -- >> Jeff Squyres >> jsquy...@cisco.com >> For corporate legal information go to: >> http://www.cisco.com/web/about/doing_business/legal/cri/ >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel >> Link to this post: >> http://www.open-mpi.org/community/lists/devel/2015/02/17012.php > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2015/02/17013.php > > > > -- > Paul H. Hargrove phhargr...@lbl.gov > Computer Languages & Systems Software (CLaSS) Group > Computer Science Department Tel: +1-510-495-2352 > Lawrence Berkeley National Laboratory Fax: +1-510-486-6900 > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2015/02/17014.php
