# Compiling Fast v8 using gfortran **URL:** \ **Category:** Computer-Aided Engineering Software Tools\ **Created:** [July 18, 2014, 7:16am UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953 "2014-07-18T07:16:21Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Bonnie.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/bonnie.jonkman/32/3230_2.png) [@Bonnie.Jonkman](https://forums.nlr.gov/u/Bonnie.Jonkman)\ **Post date:** [January 20, 2016, 4:42pm UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/21 "2016-01-20T16:42:31Z")
Hi, Ana. You can expect gfortran-generated executables to run slower than the Intel-generated ones. I just ran a comparison on my PC: test 01 takes about 3.6 seconds (Intel) compared to 10.8 seconds (gfortran), even with similar optimization options. However, looking at your output, I see some debugging information. It looks like you’ve compiled with options to give you run-time checks. This will certainly slow down the code. So, the first thing I would do is look at your FAST makefile and see what you’ve specified for FFLAGS. This is what I generally specify for production-type code: `FFLAGS = -O2 -m$(BITS) -fbacktrace -ffree-line-length-none -x f95-cpp-input LDFLAGS = -O2 -m$(BITS) -fbacktrace ` ---
**Author:** ![Ana.Fernandez](https://avatars.discourse-cdn.com/v4/letter/a/ecccb3/32.png) [@Ana.Fernandez](https://forums.nlr.gov/u/Ana.Fernandez)\ **Post date:** [January 21, 2016, 8:41am UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/22 "2016-01-21T08:41:24Z")
Thank you very much, Bonnie. With you recommendation I get a two times quicker result even if it is not as fast as yours: ![simulacionFAST_2.PNG](https://europe1.discourse-cdn.com/nrel/original/1X/a6b302a235e4a0b34d1faee89c0bd45acb601832.png) ---
**Author:** ![Mohibb.Malik](https://avatars.discourse-cdn.com/v4/letter/m/7bcc69/32.png) [@Mohibb.Malik](https://forums.nlr.gov/u/Mohibb.Malik)\ **Post date:** [January 28, 2016, 10:24am UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/23 "2016-01-28T10:24:51Z")
Hi, Ana. I am having the exact same problem as you, where the project finds the lapack/blas library, but then gives the “Skipping incompatible…” message. I tried compiling the libraries myself, following the instructions at [icl.cs.utk.edu/lapack-for-windows/lapack/](http://icl.cs.utk.edu/lapack-for-windows/lapack/), but I keep running into problems I do not understand at all. Do you think you could help me out by uploading the 64 bit lapack/blas libraries you compiled with gfortran? Thanks, Mohibb Malik ---
**Author:** ![Luke.Cunningham](https://avatars.discourse-cdn.com/v4/letter/l/5fc32e/32.png) [@Luke.Cunningham](https://forums.nlr.gov/u/Luke.Cunningham)\ **Post date:** [November 16, 2018, 5:18pm UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/24 "2018-11-16T17:18:54Z")
Hi, I have successfully compiled Fast v8 and Turbsim v2 using a gfortran compiler, and both are working very well. A strange issue has come to my attention, however. I was getting errors such as ‘Segmentation Error- core dumped’ and found the reason for this error to be the “Hdsum” flag in the OC3Hywind HydroDyn.dat file. When this flag is set to ‘True’ - no errors. When it is set to ‘False’ - I get the segmentation error. Could anyone explain why this might be happening? Thanks, Luke ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [November 28, 2018, 2:46pm UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/25 "2018-11-28T14:46:47Z")
Dear Luke, Thanks for reporting this issue. Rafael Mudafort traced this back to a minor bug in HydroDyn, which he has now fixed in OpenFAST–see: [github.com/OpenFAST/openfast/pull/207](https://github.com/OpenFAST/openfast/pull/207). Best regards, ---
**Author:** ![Luke.Cunningham](https://avatars.discourse-cdn.com/v4/letter/l/5fc32e/32.png) [@Luke.Cunningham](https://forums.nlr.gov/u/Luke.Cunningham)\ **Post date:** [December 6, 2018, 1:34pm UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/26 "2018-12-06T13:34:21Z")
Hi Jason, Great, thanks! I am now trying to compile FAST on a high performance computer using Linux to run some extensive simulations. I am running into some compilation error with FAST which I do not understand. I’m trying to follow the instructions at [github.com/old-NWTC/FAST/blob/m … owsCompile](https://github.com/old-NWTC/FAST/blob/master/Compiling/CompilingInstructions.md#NonWindowsCompile) but running into a problem. I have the Registry and MAP++ steps done. I did have to edit the make file for how MAP++ links to lapacke but the library was generated so I don’t think that is the issue. The problem I encounter is when doing a make in ~/src/FAST/Compiling leads to the following error: Registry warning: type MeshMapType used before defined for IceD\_P\_2\_SD\_P Registry warning: type MeshMapType used before defined for SD\_P\_2\_IceD\_P generating …/Source/FAST\_Types.f90 make: \*\*\* […/Source/FAST\_Types.f90] Segmentation fault make: \*\*\* Deleting file `…/Source/FAST\_Types.f90’ I’ve attached the full output from the attempted compilation here. Here are some environment details: $ gfortran --version GNU Fortran (GCC) 7.3.0 Copyright (C) 2017 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ gcc --version gcc (GCC) 7.3.0 Copyright (C) 2017 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ cat /etc/redhat-release Scientific Linux release 6.10 (Carbon) $ uname -r 2.6.32-754.3.5.el6.x86\_64 I’d really appreciate any help you can offer and sorry if I’m missing something basic or obvious. Thanks, Luke Cunningham ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [December 6, 2018, 2:07pm UTC](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953/27 "2018-12-06T14:07:01Z")
Dear Luke, I’m not sure, but this old-NWTC version of FAST is no longer supported. Hopefully switching to OpenFAST will solve your problem: [github.com/OpenFAST/openfast](https://github.com/OpenFAST/openfast). Best regards, [Previous page](https://forums.nlr.gov/t/compiling-fast-v8-using-gfortran/953.md?page=1)