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  1. SmeeBobFred

    Fortran Program Dealing with Very Large Arrays

    I don't know much about memory allocation in FORTRAN but I do know that a 32-bit program cannot usually access more than 2 GiB of RAM at once. Although a 19200x22800 array wouldn't reach that 2 GiB limit (1670 MiB), if you're using it at the same time as the 13081x21272 array, then together...
  2. SmeeBobFred

    g95 -march switch not working

    Never mind, I figured it out. I had to add my own "Platform" for x64 (I'm used to it being there automatically) in the Configuration Manager. I had to find and add some more library directories to get it to compile but it does work now. The x64 version of the program is a bit quicker and, for...
  3. SmeeBobFred

    g95 -march switch not working

    I've discovered that the reason for the slowness of my program in gfortran was due to heavy I/O. I've now removed an unneeded portion of code that was writing to a file hundreds of thousands of times and the speeds of g95 and gfortran are now very similar (g95 is still faster though). I've also...
  4. SmeeBobFred

    g95 -march switch not working

    Yeah I'm pretty sure the versions of both g95 and gfortran I have are 32-bit but g95 comes out faster every time. I've tried two different multi-threaded sections with gfortran so far, both slow the program down. I've yet to try co-arrays with g95 and I've also got a trial version of ifort to...
  5. SmeeBobFred

    Leading spaces in real format

    I don't know how useful this is for F77 but if I want to output a number I have without any leading spaces, I just do this: INTEGER :: MyInteger CHARACTER(LEN=7) :: MyString WRITE(MyString,'(i7.5)') MyInteger WRITE(6,*) 'MyInteger: ', TRIM(ADJUSTL(MyString)) Should work for real numbers too...
  6. SmeeBobFred

    g95 -march switch not working

    Thanks for the info. I tried splitting some matrix manipulation using the OpenMP and, although it seems to be splitting into worker threads correctly, it ends up being slower than the single-threaded version. I guess the time saved by splitting the manipulation into multiple threads doesn't...
  7. SmeeBobFred

    g95 -march switch not working

    Turned out all I needed to do to get gfortran to work in a batch file was restart the computer (couldn't do it before as I was waiting for other calculations to finish). I've used gfortran with the same settings as I've used with g95 (-O3 -ftree-vectorize -funroll-loops) and these are the...
  8. SmeeBobFred

    g95 -march switch not working

    The installer did finish eventually, not sure why it hanged at that point. Didn't help though, the PATH still isn't registered and if I do it manually, it still isn't recognised in a batch file.
  9. SmeeBobFred

    g95 -march switch not working

    Thanks for the link. I ran the installer but it seems to be stuck on this step: Extract: README.html Output folder: C:\Program Files (x86)\gfortran All the buttons are greyed out and I can't do anything except to End Task. It's been stuck there for 2 minutes so far...
  10. SmeeBobFred

    g95 -march switch not working

    That didn't work but adding C:\Program Files (x86)\MinGW\bin to my PATH variable lets me run it from the command prompt. However, it doesn't work when run from a batch file ("gfortran isn't a recognised command"), which I need. In fact, g95 isn't even working through a batch file now. :( Even...
  11. SmeeBobFred

    g95 -march switch not working

    The snapshot I currently have installed has "G95 (GCC 4.1.2 (g95 0.93!) Jun 16 2010)" but it has not installed gfortran with it. I tried to find gfortran by itself but couldn't - there doesn't seem to be any Windows builds available on the official releases site. Instead I just downloaded the...
  12. SmeeBobFred

    g95 -march switch not working

    Hi, I've been trying to optimise some FORTRAN code and I've managed to make it about 4 times quicker (largely due to the -O3 switch in g95). I've been trying to use the -march switch to possibly optimise further but nothing I set it equal to is recognised. This is my basic compile command: g95...

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