On Sunday 09 March 2003 03:57, Steve Harris wrote: > On Sun, Mar 09, 2003 at 01:26:38 +0200, Jaakko Prättälä wrote: > > > > I think there'll be no problems with the precision since > > (to my knowledge) double precision is fftw's default. > > Maybe swh's configure-script should look for 'd'-prefixed files too? > > I think single used to be the default. Double, /may/ work but it will be > slow if it does. > > The FFTW people should really sort this out. I totally agree, but the latest fftw (2.1.3) release is from 1999 :-) I'm quite sure that the default for fftw is _double_, unless you specify --enable-float for the build. Here are some findings to support this presumption: These babblings are not so relevant, but I included them for completeness' sake... <cryptic_cyberbabble> - from the default fftw.h (no configure-script options, fftw version 2.1.3): /* Define for using single precision */ /* * If you can, use configure --enable-float instead of changing this * flag directly */ /* #undef FFTW_ENABLE_FLOAT */ /* our real numbers */ #ifdef FFTW_ENABLE_FLOAT typedef float fftw_real; #else typedef double fftw_real; #endif - make |grep "FFTW_ENABLE_FLOAT" produces no output other than compiler warnings. </cryptic_cyberbabble> ...but the next says a lot: - from the faq (fftw-2.1.3/FAQ/fftw-faq.ascii): Question 2.9. How do I compile FFTW to run in single precision? On a Unix system: configure --enable-float. On a non-Unix system: edit fftw/fftw.h to #define the symbol FFTW_ENABLE_FLOAT. In both cases, you must then recompile FFTW. The logical solution would be to build one's fftw with ./configure --enable-shared --enable-float --enable-type-prefix and make non-prefixed symlinks to the double version. In this case (I have symlinks to the shared lib), Steve, your configure-script says checking for fftw_one in -lsfftw... (cached) no checking for fftw_one in -lfftw... (cached) yes (strange) so I guess it will link against the double-precision version of the lib. I haven't gotten into testing imp or pitch_scale yet, so I can't say if there are any problems with this. Last night I tried out delay-o-rama + flanger. Tapping a mic never sounded so good :-) -- Jaakko Prättälä Jaakko.Prattala@xxxxxxxxxxx