Windows Installation Notes

This document contains various information regarding installation of FFTW on DOS/Windows. (It was sent in by users, and has not been personally verified by us.) Please contact us if you have any additions or corrections. You should, of course, first read the Installation on non-Unix Systems of the FFTW 3 manual (or the corresponding section of the FFTW 2 manual).

FFTW 3.x Windows binaries

Franz Franchetti has graciously offered to provide up-to-date FFTW binaries and project files using Visual Studio and the Intel C compiler at his web page.

Alessio Massaro contributed Windows binaries of fftw-3.0.1, compiled with the Intel C Compiler version 7.1. This package uses SSE/SSE2 instructions when appropriate.

This archive is called fftw-3.0.1-w32-pl1.zip and was created on Nov 13, 2003. If you downloaded the older archive fftw-3.0.1-w32.zip, please upgrade. Some library symbols were incorrectly not exported in the older build.

Alessio has also sent us Windows binaries compiled with gcc under MinGW, which support for threads and have AMD K7 (3dNow!) in addition to SSE/SSE2. An updated version of this file was contributed by Boran Car, which incorporates a missing libgcc.a library file. This library can be called from Visual C++ and other Windows compilers.

Klaus Maisinger contributed .def and .lib files for Borland C++ Builder 6 to to allow you to use the above Intel-compiled binaries; you need to use Klaus' fftw3.lib in addition to fix compatibility problems between Borland C++ and Visual C++. See also his description of what he did.

The above binaries were, unfortunately, compiled without the Fortran wrapper routines. Koos Huijssen sent us a library file for Compaq Visual Fortran that you can use, in addition to Alessio's DLL, to call FFTW from that Fortran compiler.

FFTW 3.x and Visual C++

Stephane Ruel helped us to get FFTW 3 working under Visual C++, and sent us a build file to compile FFTW with that compiler. (Note that this package provides modified versions of some FFTW files, which are no longer necessary with FFTW version 3.0.1. Also, it refers to the files rdft/vrank2-transpose.c and rdft/vrank3-transpose.c, which are no longer included or needed; references to them should be deleted from the build, or you can create empty files with these names. Other compiler warnings can be ignored.)

Mark Roden send us modified build files to use Visual C++ 6.0 with version 8.0 of the Intel compiler and FFTW 3.0.1, with threads and SSE enabled.

Visual C++ Problems

Visual C++ is buggy. Get a real compiler and do not complain to us.

Stephane Ruel was unable to get the SIMD (SSE) code to produce correct results with Visual C++ 6.0; we suspect a compiler bug (the same code works fine with gcc and Intel icc). We have an unconfirmed report of similar problems with version 7.0. If you have a more recent version of VC++, please let us know whether it works.

Stephane recently reported that he was able to compile the SIMD code in FFTW 3.0.1 using the Intel compiler version 7.1 (with flags -O3 -G7 -QxW) with Visual C++. (Modify config.h to #define either HAVE_SSE or HAVE_SSE2, depending upon the precision.)

Visual C++ 4.0 and 5.0 had some problems compiling previous FFTW versions correctly, but these were fixed in later releases of those compilers, which however introduced new bugs for new FFTW versions.

VC++ 6.0 also reportedly produces incorrect code for the file reodft11e-r2hc-odd.c (odd-size type-IV DCTs and DSTs) unless optimizations are disabled for that file.

Visual C++ Project Files and Win32 Binaries for FFTW 2.x

You should note that the FFTW package can be compiled as-is on Windows--you simply need to compile all of the .c files in the fftw and rfftw directories. Andrew's files may provide extra convenience, however, especially when building DLLs.

Andrew's package also includes some code to allow the test program to accept command-line parameters in the DOS shell (otherwise, the test program will run in interactive mode on Windows).

You can also find the latest versions of Andrew's packages, as well as prebuilt binaries for Win32 (x86) on his web site.

FFTW 3.x and Borland Delphi

George Beckett has contributed a Pascal interface file (fftw_interface.pas) for calling FFTW from Borland Delphi (Pascal). This file is for the single-precision FFTW, but double-precision could be used as well by changing the appropriate types and renaming fftwf_ to fftw_ in the file.

He also sent us his notes on calling FFTW from Delphi as well as on compiling FFTW on Windows with the Borland C++ compiler. Finally, he sent us the compiled library via Borland (see also the material from Klaus Maisinger, above). George recommends using the DLLs from Alessio Massaro instead, though, for better performance (note that Alessio's symbol names do not need to be prepended with an underscore, however).

FFTW 2.x and Dev-C++/MinGW

Marek Januszewski has created an FFTW 2.x DevPak for use with Dev-C++ (a MinGW front-end).

Alignment with FFTW 2.x

FFTW includes special hacks to align double-precision variables on the stack for gcc on x86. One of our users, Jonathan Hardwick, has done a detailed study of how these hacks might be extended to Visual C++ and the Intel C++ compiler, and what their performance effects are.

Fortran with FFTW 2.x

FFTW can include Fortran-callable wrapper routines so that you can call the FFTW functions from a Fortran program. These routines are not available automatically on Windows, however.

The problem is that FFTW does not know how to mangle its subroutine names for the Fortran linker (Fortran expects all identifiers to be in a canonical case and format). On Unix systems, our configure script can automatically detect the name-mangling scheme, but this is not possible on Windows. So, you have to specify it manually in order to use the Fortran wrappers.

To do this, go to the end of the fftw/config.h file and #define the appropriate symbol according to the comments. There are eight possibilities: all upper or lower case, and zero, one, or two appended underscores. For example, Digital Visual Fortran (reportedly) uses all lower case with no appended underscore, so you should #define FFTW_FORTRANIZE_LOWERCASE. (If you don't know, you can experiment with a small Fortran and C program until you find something that works. Your Fortran manual may also document how to link with C.) Let us know how it works with your Fortran compiler.

There is another issue to be aware of with Digital Fortran: for every routine that you want to call (e.g. fftw_f77), you must include an instruction like the following at the beginning of your Fortran program:

!DEC$ ATTRIBUTES C, REFERENCE :: fftw_f77

(Thanks to Dima Berkov for this note.)

Timer with FFTW 2.x

FFTW includes a high-precision timer that will be automatically (see below) enabled under Win32, contributed by Andrew Sterian.

We have not tested this code ourselves, however, and it may cause problems for some users. (In particular, problems have been reported with its use of the header file windows.h, which is not recognized in some configurations.) To disable the use of this timing code (and revert to the default clock() function), comment out the line:

#define HAVE_WIN32_TIMER

If you want to make sure that the timer is automatically enabled in your compiler, delete the #if directive surrounding the above line. (This directive is used to automatically enable the timer, but it won't work if your compiler doesn't define __WIN32__, WIN32, or _WINDOWS. Visual C++ and Borland C/C++ should be fine.)

Watcom with FFTW 2.x

FFTW 1.2

Here are some changes to the Makefile sent in by Robert Jansen to get FFTW 1.2 running under the DOS shell with gcc:

• RM = del
• CP = copy
• AR = ar
• In the library compilation part, use:

  $(AR) rv $(LIBFFT) *.o
  

  due to argument number constraints in make (there are likely other work-arounds).
• Change $(RM) -f to $(RM)
• Remove all _64 modules in config.c and the Makefile due to a stack limit problem. (This might be solved by simply increasing the stack size in config.sys; he didn't check.)