Version 2.1.5 (3/24/2003) * Bug fix: Fortran wrappers were disabled in version 2.1.4. Version 2.1.4 (3/16/2003) * Upgraded to newer versions of autoconf, etcetera, to fix compilation problems on various recent systems. * The configure script no longer picks the wrong architecture flags (which caused FFTW to crash) on newer IBM POWER machines running AIX. * Multi-threaded transforms should now utilize multiple CPUs on Solaris (which creates threads in single-processor mode by default). * Added experimental support for OpenMP (and SGI MP) compiler parallelization directives in the multi-threaded transforms, instead of using explicit thread spawning. Enable by configuring --with-openmp or --with-sgi-mp in addition to --enable-threads. * Expanded FAQ. Version 2.1.3 (11/7/1999) * The configure script no longer overrides the CFLAGS environment variable if it is defined. (Thanks to Diab Jerius.) * Experimental Fortran-callable wrapper routines for MPI FFTW. See mpi/README.f77 for more information. * The configure script now detects and works around a stack alignment bug in gcc 2.95.x on x86. * configure attempts to guess the appropriate -mcpu flag on Linux/PPC systems, improving performance (especially on G3s with gcc 2.95 or later). * Fixed integer overflow bug for complex transforms of large prime sizes (> 32768). Thanks to Ezio Riva for the bug report. * Fixed memory leak in the Matlab wrappers; thanks to Matthew Davis for the bug report. * Fixed bugs in the configure script when detecting POSIX threads libraries on AIX and Tru64 (nee Digital) Unix. * Fixed bug in multi-threaded transforms on AIX (which strangely creates threads in non-joinable mode by default). Thanks to Jim Lindsay for the bug report, and for allowing us to debug on Northwestern University's IBM SP2. * Slight fix to help build DLL's on Win32 (thanks to Andrew Sterian). Version 2.1.2 (5/18/1999) * Fixed bug in our MPI test programs which made them fail under MPICH with the p4 device (TCP/IP). (The 2.1.1 transforms worked, but the test programs crashed.) * Added missing fftw_f77_threads_init function to the Fortran wrappers for the multi-threaded transforms. Thanks to V. Sundararajan for the bug report. * The codelet generator can now output efficient hard-coded DCT/DST transforms. As a side effect of this work, we slightly reduced the code size of rfftw. * Test programs now support GNU-style long options when used with glibc. * Added some more ideas to our TODO list. * Improved codelet generator speed. Version 2.1.1 (3/31/1999) * Fixed bug in the complex transforms for certain sizes with intermediate-length prime factors (17-97), which under some (hopefully rare) circumstances could cause incorrect results. Thanks to Ming-Chang Liu for the bug report and patch. (The test program will now catch this sort of problem when it is run in paranoid mode.) Version 2.1 (3/8/1999) * Added Fortran-callable wrapper routines for the multi-threaded transforms. * Documentation fixes and improvements. * The --enable-type-prefix option to configure makes it easy to install both single- and double-precision versions of FFTW on the same (Unix) system. (See the installation section of the manual.) * The MPI FFTW routines now include parallel one-dimensional transforms for complex data. (See the fftw_mpi documentation in the FFTW manual.) * The MPI FFTW routines now include parallel multi-dimensional transforms specialized for real data. (See the rfftwnd_mpi documentation in the FFTW manual.) * The MPI FFTW routines are now documented in the main manual (in the doc directory). On Unix systems, they are also automatically configured, compiled, and installed along with the main FFTW library when you include --enable-mpi in the flags to the configure script. (See the FFTW manual.) * Largely-rewritten MPI code. It is now cleaner and (sometimes) faster. It also supports the option of a user-supplied workspace for (often) greater performance (using the MPI_Alltoall primitive). Beware that the interfaces have changed slightly, however. * The multi-threaded FFTW routines now include parallel one- and multi-dimensional transforms of real data. (See the rfftw_threads documentation in the FFTW manual.) * The multi-threaded FFTW routines are now documented in the main manual (in the doc directory). On Unix systems, they are also automatically configured, compiled, and installed along with the main FFTW library when you include --enable-threads in the flags to the configure script. (See the FFTW manual.) * The multi-threaded FFTW routines now include support for Mach C threads (used, for example, in Apple's MacOS X). * The Fortran-callable wrapper routines are now incorporated into the ordinary FFTW libraries by default (although you can disable this with the --disable-fortran option to configure) and are documented in the main FFTW manual. * Added an illustration of the data layout to the rfftwnd tutorial section of the manual, in the hope of preventing future confusion on this subject. * The test programs now allow you to specify multidimensional sizes (e.g. 128x54x81) for the -c and -s correctness and speed test options. Version 2.0.1 (9/29/98) * (bug fix) Due to a poorly-parenthesized expression, rfftwnd overflowed 32-bit integer precision for rank > 1 transforms with a final dimension >= 65536. This is now fixed. (Thanks to Walter Brisken for the bug report.) * (bug fix) Added definition of FFTW_OUT_OF_PLACE to fftw.h. The flag is mentioned several times in the documentation, but its definition was accidentally omitted since FFTW_OUT_OF_PLACE is the default behavior. * Corrected various small errors in the documentation. Thanks to Geir Thomassen and Jeremy Buhler for their comments. * Improved speed of the codelet generator by orders of magnitude, since a user needed a hard-coded fft of size 101. * Modified buffering in multidimensional transforms for some speed improvements (only when fftwnd_create_plan_specific is used). Thanks to Geert van Kempen for his tips. * Added Andrew Sterian's patch to allow FFTW to be used as a shared library more easily on Win32. Version 2.0 (9/11/1998) * Completely rewritten real-complex transforms, now using specialized codelets and an inherently real-complex algorithm for greatly increased speed. Also, rfftw can now handle odd sizes and strided transforms. Beware that the output format for 1D rfftw transforms has changed. See the manual for more details. * The complex transforms now use a fast algorithm for large prime factors, working in O(N lg N) time even for prime sizes. (Previously, the complexity contained an O(p^2) term, where p is the largest prime factor of N. This is still the case for the rfftw transforms.) Small prime factors are still more efficient, however. * Added functions fftw_one, fftwnd_one, rfftw_one, etcetera, to simplify and clarify the use of fftw for single, unit-stride transforms. * Renamed FFTW_COMPLEX, FFTW_REAL to fftw_complex, fftw_real (for greater consistency in capitalization). The all-caps names will continue to be supported indefinitely, but are deprecated. (Also, support for the COMPLEX and REAL types from FFTW 1.0 is now disabled by default.) * There are now Fortran-callable wrappers for the rfftw real-complex transforms. * New section of the manual discussing the use of FFTW with multiple threads, and a new FFTW_THREADSAFE flag (described therein). * Added shared library support. Use configure --enable-shared to produce a shared library instead of a static library (the default). * Dropped support for the operation-count (*_op_count) routines introduced in v1.3, as these were little-used and were a pain to keep up-to-date as FFTW changed internally. * Made it easier to support floating-point types other than float and double (e.g. long double). (See the file fftw-int.h.) Version 1.3 (4/9/1998) * Multi-dimensional transforms contain significant performance improvements for dimensions >= 3. * Performance improvements in multi-dimensional transforms with howmany > 1 and stride > dist. * Improved parallelization and performance in the threads code for dimensions >= 3. * Changed the wisdom import/export format (the new wisdom remembers the stride of the plan that generated it, for use with the new create_plan_specific functions). (You should regenerate any stored wisdom you have anyway, since this is a new version of FFTW.) * Several small fixes to aid compilation on some systems. * Fixed a bug in the MPI transform (in the transpose routine) that caused errors for some array sizes. * Fixed the (hopefully) last few things causing problems with C++ compilers. * Hack for x86/gcc to properly align local double-precision variables. * Completely rewritten codelet generator. Now it produces better code for non powers of 2, and is ready to produce real->complex transforms. * Testing algorithm is now more robust, and has a more rigorous theoretical foundation. (Bugs in testing large transforms or in single precision are now fixed--these bugs were only in the test programs and not in the FFTW library itself.) * Added "specific" planners, which allow plan optimization for a specific array/stride. They also reduce the memory requirements of the planner, and permit new optimizations in the multi-dimensional case. (See the *_create_plan_specific functions.) * FFTW can now compute a count of the number of arithmetic operations it requires, which is useful for some academic purposes. (See the *_count_plan_ops functions.) * Adapted for use with GNU autoconf to aid installation on UNIX systems. (Installation on non-UNIX systems should be the same as before.) * Used gettimeofday function if available. (This function typically has much higher accuracy than clock(), permitting plans to be created much more quickly than before on many machines.) * Made timing algorithm (hopefully) more robust in the face of system interrupts, etc. * Added wrapper routines for calling FFTW from MATLAB (in the matlab/ directory). * Added wrapper routines for calling FFTW from Fortran (in the fortran/ directory). (These were available separately before.) Version 1.2.1 (12/4/1997) * Fixed a third bug in the mpi transpose routines (sheesh!) that could cause problems when re-using a transpose plan. Thanks to Eric Skyllingstad for the bug reports. * Fixed another bug in the mpi transpose routines. This bug produced a memory leak and also occasionally tries to free a null pointer, which causes problems on some systems. The mpi transpose/fft routines now pass all of our malloc paranoia tests. * Fixed bug in mpi transpose routines, where wrong results could be given for some large 2D arrays. Version 1.2 (9/8/1997) * Added a FAQ (in the FAQ/ directory). * Fixed bug in rfftwnd routines where a block was accidentally allocated to be too small, causing random memory to be overwritten (yikes!). (Amazingly, this bug only caused the test program to fail on one system that we could find. Our test suite can now catch this sort of bug.) * Abstractified taking differences of times (with fftw_time_diff macro/function) to allow more general timer data structures. * Added "wisdom" mechanism for saving plans & related info. * Made timing mechanism more robust and maintainable. (Instead of using a fixed number of iterations, we now repeatedly double the number of iterations until a specified time interval (FFTW_TIME_MIN) is reached.) * Fixed header files to prevent difficulties when a mix of C and C++ compilers is used, and to prevent problems with multiple inclusions. * Added experimental distributed-memory transforms using MPI. * Fixed memory leak in fftwnd_destroy_plan (reported by Richard Sullivan). Our test programs now all check for leaks. Version 1.1 (5/5/1997) * Improved speed (yes!) [Some clever tricks with twiddle factors and better code generator] * Renamed `blocks' to `codelets', just to be fashionable * Rewritten planner and executor--much simpler and more readable code. Reference-counter garbage collection employed throughout. * Much improved codelet generator. The ML code should be now readable by humans, and easier to modify. * Support for Prime Factor transforms in the codelet generator. * Renamed COMPLEX -> FFTW_COMPLEX to avoid clashes with existing packages. COMPLEX is still supported for compatibility with 1.0 * Added experimental real->complex transform (quick hack, use at your own risk). * Added experimental parallel transforms using Cilk. * Added experimental parallel transforms using threads (currently, POSIX threads and Solaris threads are implemented and tested). * Added DOS support, in the sense that we now support 8.3 filenames. Version 1.0 (3/24/1997) * First release.