Re: gfortran produces huge executables

<hermantobin@[EMAIL PROTECTED]
> wrote in message
news:370068ea-415b-40a8-a330-3d3c8011819c@[EMAIL PROTECTED]
> I'm new to Fortran (typically use Java and C++).   I'm have compiled
> some F90 molecular dynamics code that has been passed down.  gfortran
> produces huge (700 megabyte) executable files, while a trial version
> of ifort produces an executable file under 1 meg.  The executable runs
> in either case, but the large file size and compile+link times are a
> nuisance. The large executable is likely related to a single large
> object file, which is associated with a source file that defines a
> large dynamically allocated (I believe) array.  Maybe this is some
> flag that I have failed to set?
>
> gfortran version: GNU Fortran (GCC) 4.3.0 20070810 (experimental)
> OS: Intel OS X 10.5.2
> Processor: 2.16 GHz Intel Core 2 Duo


"gFortran executable size" depends on how gfortran is built. It could be
small, and could be huge as you experienced. It totally depends on where
you
download the compiler. If you are on Windows, you can download gfortran
and
c++ at www.Equation.com. The compiler built by Equation.com will produce a
small-sized executable.

As compared to ifort, gFortran may produce a smaller executable. I post an
example in the following

04/26/08  04:01p               293,376 bench1_gfortran.exe
04/25/08  07:14a               667,648 bench1_intel.exe

Both EXEs are from the same source code, and static link. It can be seen
gfortran produces a smaller executable in this example. ifort has a better
optimization. For example, EXE from gfortran takes 105 seconds on one
processor, and EXE from ifort can finish it about 51 seconds (on a baby
200
MHZ dual pentium pro). The EXEs have classic pentium instructions. In this
example, ifort shows 2X faster. (On some applications, ifort can be up to
6X)



**** EXE by gfortran ****

C:\TEMP>bench1_gfortran
 number of equations:      2000000
 Half bandwidth:            8

 Processor:  1
 Elapsed Time (Seconds):   105.05
 CPU Time in User Mode (Seconds):   104.05
 CPU Time in Kernel Mode (Seconds):     1.00
 Total CPU Time (Seconds):   105.05

 Processors:  2
 Elapsed Time (Seconds):    52.55
 CPU Time in User Mode (Seconds):   104.19
 CPU Time in Kernel Mode (Seconds):     0.89
 Total CPU Time (Seconds):   105.08



*** EXE by ifot ***

C:\TEMP>bench1_intel
 number of equations:      2000000
 Half bandwidth:            8

 Processor:  1
 Elapsed Time (Seconds):    51.51
 CPU Time in User Mode (Seconds):    50.42
 CPU Time in Kernel Mode (Seconds):     1.09
 Total CPU Time (Seconds):    51.52

 Processors:  2
 Elapsed Time (Seconds):    26.28
 CPU Time in User Mode (Seconds):    51.80
 CPU Time in Kernel Mode (Seconds):     0.69
 Total CPU Time (Seconds):    52.48