code speed moving from fortran 77 compiler to f2003 compiler
in [Fortran]
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From: Lynn McGuire on 25 Jun 2010 13:02 > Just to clarify: are you staying with Open Watcom F77 and not trying > to port to Fortran 2003? I was awaiting reports of differences in > speed with the Fortran 2003 version. Ah , well. For the moment. Our code just works here. But, I am considering trying out the Absoft fortran compiler ( http://absoft.com/ ) as it has a good rep. My long term goal is to convert our F77 code to C++ using FOR_C. We may be trying this later this year when all of our Hollerith code is gone. > An old technique, but if it works it works! I have found that improvements in the algorithm are always superior to code optimization. But, the automatic vectorization in Absoft sounds interesting. Thanks, Lynn
From: Colin Paul Gloster on 25 Jun 2010 13:47 On Fri, 25 Jun 2010, Lynn McGuire sent: |-------------------------------------------------------------------| |"[..] | | | |My long term goal is to convert our F77 code to C++ using FOR_C. | |[..]" | |-------------------------------------------------------------------| Using C++ is a bad idea. |-------------------------------------------------------------------| |"> An old technique, but if it works it works! | | | |I have found that improvements in the algorithm are always superior| |to code optimization. [..] | |[..]" | |-------------------------------------------------------------------| One does not always have that option.
From: Lynn McGuire on 25 Jun 2010 14:45 > |My long term goal is to convert our F77 code to C++ using FOR_C. | > |[..]" | > > Using C++ is a bad idea. Why ? Half of our app is already in C++. We have 600,000 lines of f77 code and 600,000 lines of c++ code. The c++ code is far easier to maintain and code in. Thanks, Lynn
From: Ron Shepard on 25 Jun 2010 19:29 In article <i02tfs$rv3$1(a)news.eternal-september.org>, Lynn McGuire <lmc(a)winsim.com> wrote: > > Using C++ is a bad idea. > > Why ? Half of our app is already in C++. We have 600,000 > lines of f77 code and 600,000 lines of c++ code. The c++ > code is far easier to maintain and code in. After looking at your f77 code (with all of its nonstandard extensions) that you have posted here, I would say that is damnation by faint praise. $.02 -Ron Shepard
From: Gordon Sande on 25 Jun 2010 20:19
On 2010-06-25 20:29:11 -0300, Ron Shepard <ron-shepard(a)NOSPAM.comcast.net> said: > In article <i02tfs$rv3$1(a)news.eternal-september.org>, > Lynn McGuire <lmc(a)winsim.com> wrote: > >>> Using C++ is a bad idea. >> >> Why ? Half of our app is already in C++. We have 600,000 >> lines of f77 code and 600,000 lines of c++ code. The c++ >> code is far easier to maintain and code in. > > After looking at your f77 code (with all of its nonstandard > extensions) that you have posted here, I would say that is damnation > by faint praise. > > $.02 -Ron Shepard Les Hatton (he has a web site) has published reports on studies of production codes in oil exploration. C, C++ and Fortran with Fortran causing least problems. Various others have reported that C++ is a real bear with two caveats 1. no use of object inheritance 2. serious objects only when objects are very well designed such as the (many-ith iteration) of a design such as windows and the design is now static and widely used. Basically C++ is impossible to read/maintain is there is any serious local use of objects as one no longer knows what the code is doing with only a local inspection. |