On 12/17/18, Thomas Grill gr@grrrr.org wrote:
No time to check deeper now, but to my surprise CFLAGS "-D PD_FLOATSIZE=64" ./configure && make does indeed compile from the vanilla git repo (but doesn't link with portmidi and portaudio for other reasons). The definitions in m_pd.h suggest that t_float becomes double...
Successful compilation with 64 bit floats is a first step but doesn't tell so much in itself. By the way it is better to override CPPFLAGS, not CFLAGS (which holds important flags):
$ make CPPFLAGS="-D PD_FLOATSIZE=64"
This builds Pd with 64 bit floats indeed. The question is, to what extent does it work? This page provides a .zip with some test patches that illustrate hotspots of precision problems:
https://katjaas.nl/doubleprecision/doubleprecision.html
The patches were made in 2011 to test pd-double but they are still useful. For example patch "03precision-tests/limits.pd" gives proof of double precision when showing very small and large numbers that single precision can't do.
Though Pd 0.49 compiled as above shows those small and large numbers, it can't show all significant decimals in the GUI. This of course limits the usefulness of double precision and also complicates the interpretation of other tests.
Katja