Home | Back
FFTW 3.1.3

* Bug fix: FFTW computes incorrect results when the user plans both
  REDFT11 and RODFT11 transforms of certain sizes.  The bug is caused
  by incorrect sharing of twiddle-factor tables between the two
  transforms, and only occurs when both are used.  Thanks to Paul
  A. Valiant for the bug report.

FFTW 3.1.2

* Correct bug in configure script: --enable-portable-binary option was ignored!
  Thanks to Andrew Salamon for the bug report.

* Threads compilation fix on AIX: prefer xlc_r to cc_r, and don't use
  either if we are using gcc.  Thanks to Guy Moebs for the bug report.

* Updated FAQ to note that Apple gcc 4.0.1 on MacOS/Intel is broken,
  and suggest a workaround.  configure script now detects Core/Duo arch.

* Use -maltivec when checking for altivec.h.  Fixes Gentoo bug #129304,
  thanks to Markus Dittrich.

FFTW 3.1.1

* Performance improvements for Intel EMT64.

* Performance improvements for large-size transforms with SIMD.

* Cycle counter support for Intel icc and Visual C++ on x86-64.

* In fftw-wisdom tool, replaced obsolete --impatient with --measure.

* Fixed compilation failure with AIX/xlc; thanks to Joseph Thomas.

* Windows DLL support for Fortran API (added missing __declspec(dllexport)).

* SSE/SSE2 code works properly (i.e. disables itself) on older 386 and 486
  CPUs lacking a CPUID instruction; thanks to Eric Korpela.

FFTW 3.1

* Faster FFTW_ESTIMATE planner.

* New (faster) algorithm for REDFT00/RODFT00 (type-I DCT/DST) of odd size.

* "4-step" algorithm for faster FFTs of very large sizes (> 2^18).

* Faster in-place real-data DFTs (for R2HC and HC2R r2r formats).

* Faster in-place non-square transpositions (FFTW uses these internally
  for in-place FFTs, and you can also perform them explicitly using
  the guru interface).

* Faster prime-size DFTs: implemented Bluestein's algorithm, as well
  as a zero-padded Rader variant to limit recursive use of Rader's algorithm.

* SIMD support for split complex arrays.

* Much faster Altivec/VMX performance.

* New fftw_set_timelimit function to specify a (rough) upper bound to the
  planning time (does not affect ESTIMATE mode).

* Removed --enable-3dnow support; use --enable-k7 instead.

* FMA (fused multiply-add) version is now included in "standard" FFTW,
  and is enabled with --enable-fma (the default on PowerPC and Itanium).

* Automatic detection of native architecture flag for gcc.  New
  configure options: --enable-portable-binary and --with-gcc-arch=<arch>,
  for people distributing compiled binaries of FFTW (see manual).

* Automatic detection of Altivec under Linux with gcc 3.4 (so that
  same binary should work on both Altivec and non-Altivec PowerPCs).

* Compiler-specific tweaks/flags/workarounds for gcc 3.4, xlc, HP/UX,

* Various documentation clarifications.

* 64-bit clean.  (Fixes a bug affecting the split guru planner on
  64-bit machines, reported by David Necas.)

* Fixed Debian bug #259612: inadvertent use of SSE instructions on
  non-SSE machines (causing a crash) for --enable-sse binaries.

* Fixed bug that caused HC2R transforms to destroy the input in
  certain cases, even if the user specified FFTW_PRESERVE_INPUT.

* Fixed bug where wisdom would be lost under rare circumstances,
  causing excessive planning time.

* FAQ notes bug in gcc-3.4.[1-3] that causes FFTW to crash with SSE/SSE2.

* Fixed accidentally exported symbol that prohibited simultaneous
  linking to double/single multithreaded FFTW (thanks to Alessio Massaro).

* Support Win32 threads under MinGW (thanks to Alessio Massaro).

* Fixed problem with building DLL under Cygwin; thanks to Stephane Fillod.

* Fix build failure if no Fortran compiler is found (thanks to Charles
  Radley for the bug report).

* Fixed compilation failure with icc 8.0 and SSE/SSE2.  Automatic
  detection of icc architecture flag (e.g. -xW).

* Fixed compilation with OpenMP on AIX (thanks to Greg Bauer).

* Fixed compilation failure on x86-64 with gcc (thanks to Orion Poplawski).

* Incorporated patch from FreeBSD ports (FreeBSD does not have memalign,
  but its malloc is 16-byte aligned).

* Cycle-counter compilation fixes for Itanium, Alpha, x86-64, Sparc,
  MacOS (thanks to Matt Boman, John Bowman, and James A. Treacy for
  reports/fixes).  Added x86-64 cycle counter for PGI compilers,
  courtesy Cristiano Calonaci.

* Fix compilation problem in test program due to C99 conflict.

* Portability fix for import_system_wisdom with djgpp (thanks to Juan
  Manuel Guerrero).

* Fixed compilation failure on MacOS 10.3 due to getopt conflict.

* Work around Visual C++ (version 6/7) bug in SSE compilation;
  thanks to Eddie Yee for his detailed report.

Changes from FFTW 3.1 beta 2:

* Several minor compilation fixes.

* Eliminate FFTW_TIMELIMIT flag and replace fftw_timelimit global with
  fftw_set_timelimit function.  Make wisdom work with time-limited plans.

Changes from FFTW 3.1 beta 1:

* Fixes for creating DLLs under Windows; thanks to John Pavel for his feedback.

* Fixed more 64-bit problems, thanks to John Pavel for the bug report.

* Further speed improvements for Altivec/VMX.

* Further speed improvements for non-square transpositions.

* Many minor tweaks.

FFTW 3.0.1

* Some speed improvements in SIMD code.

* --without-cycle-counter option is removed.  If no cycle counter is found,
  then the estimator is always used.  A --with-slow-timer option is provided
  to force the use of lower-resolution timers.

* Several fixes for compilation under Visual C++, with help from Stefane Ruel.

* Added x86 cycle counter for Visual C++, with help from Morten Nissov.

* Added S390 cycle counter, courtesy of James Treacy.

* Added missing static keyword that prevented simultaneous linkage
  of different-precision versions; thanks to Rasmus Larsen for the bug report.

* Corrected accidental omission of f77_wisdom.f file; thanks to Alan Watson.

* Support -xopenmp flag for SunOS; thanks to John Lou for the bug report.

* Compilation with HP/UX cc requires -Wp,-H128000 flag to increase
  preprocessor limits; thanks to Peter Vouras for the bug report.

* Removed non-portable use of 'tempfile' in fftw-wisdom-to-conf script;
  thanks to Nicolas Decoster for the patch.

* Added 'make smallcheck' target in tests/ directory, at the request of
  James Treacy.

FFTW 3.0

Major goals of this release:

* Speed: often 20% or more faster than FFTW 2.x, even without SIMD (see below).

* Complete rewrite, to make it easier to add new algorithms and transforms.

* New API, to support more general semantics.

Other enhancements:

* SIMD acceleration on supporting CPUs (SSE, SSE2, 3DNow!, and AltiVec).
(With special thanks to Franz Franchetti for many experimental prototypes
  and to Stefan Kral for the vectorizing generator from fftwgel.)

* True in-place 1d transforms of large sizes (as well as compressed
  twiddle tables for additional memory/cache savings).

* More arbitrary placement of real & imaginary data, e.g. including
  interleaved (as in FFTW 2.x) as well as separate real/imag arrays.

* Efficient prime-size transforms of real data.

* Multidimensional transforms can operate on a subset of a larger matrix,
  and/or transform selected dimensions of a multidimensional array.

* By popular demand, simultaneous linking to double precision (fftw),
  single precision (fftwf), and long-double precision (fftwl) versions
  of FFTW is now supported.

* Cycle counters (on all modern CPUs) are exploited to speed planning.

* Efficient transforms of real even/odd arrays, a.k.a. discrete
  cosine/sine transforms (types I-IV).  (Currently work via pre/post
  processing of real transforms, ala FFTPACK, so are not optimal.)

* DHTs (Discrete Hartley Transforms), again via post-processing
  of real transforms (and thus suboptimal, for now).

* Support for linking to just those parts of FFTW that you need,
  greatly reducing the size of statically linked programs when
  only a limited set of transform sizes/types are required.

* Canonical global wisdom file (/etc/fftw/wisdom) on Unix, along
  with a command-line tool (fftw-wisdom) to generate/update it.

* Fortran API can be used with both g77 and non-g77 compilers

* Multi-threaded version has optional OpenMP support.

* Authors' good looks have greatly improved with age.

Changes from 3.0beta3:

* Separate FMA distribution to better exploit fused multiply-add instructions
  on PowerPC (and possibly other) architectures.

* Performance improvements via some inlining tweaks.

* fftw_flops now returns double arguments, not int, to avoid overflows
  for large sizes.

* Workarounds for automake bugs.

Changes from 3.0beta2:

* The standard REDFT00/RODFT00 (DCT-I/DST-I) algorithm (used in
  FFTPACK, NR, etcetera) turns out to have poor numerical accuracy, so
  we replaced it with a slower routine that is more accurate.

* The guru planner and execute functions now have two variants, one that
  takes complex arguments and one that takes separate real/imag pointers.

* Execute and planner routines now automatically align the stack on x86,
  in case the calling program is misaligned.

* README file for test program.

* Fixed bugs in the combination of SIMD with multi-threaded transforms.

* Eliminated internal fftw_threads_init function, which some people were
  calling accidentally instead of the fftw_init_threads API function.

* Check for -openmp flag (Intel C compiler) when --enable-openmp is used.

* Support AMD x86-64 SIMD and cycle counter.

* Support SSE2 intrinsics in forthcoming gcc 3.3.

Changes from 3.0beta1:

* Faster in-place 1d transforms of non-power-of-two sizes.

* SIMD improvements for in-place, multi-dimensional, and/or non-FFTW_PATIENT

* Added support for hard-coded DCT/DST/DHT codelets of small sizes; the
  default distribution only includes hard-coded size-8 DCT-II/III, however.

* Many minor improvements to the manual.  Added section on using the
  codelet generator to customize and enhance FFTW.

* The default 'make check' should now only take a few minutes; for more
  strenuous tests (which may take a day or so), do 'cd tests; make bigcheck'.

* fftw_print_plan is split into fftw_fprint_plan and fftw_print_plan, where
  the latter uses stdout.

* Fixed ability to compile with a C++ compiler.

* Fixed support for C99 complex type under glibc.

* Fixed problems with alloca under MinGW, AIX.

* Workaround for gcc/SPARC bug.

* Fixed multi-threaded initialization failure on IRIX due to lack of
  user-accessible PTHREAD_SCOPE_SYSTEM there.