summaryrefslogtreecommitdiff
path: root/py/formatfloat.h
AgeCommit message (Collapse)Author
7 dayspy/formatfloat: Improve accuracy of float formatting code.Yoctopuce dev
Following discussions in PR #16666, this commit updates the float formatting code to improve the `repr` reversibility, i.e. the percentage of valid floating point numbers that do parse back to the same number when formatted by `repr` (in CPython it's 100%). This new code offers a choice of 3 float conversion methods, depending on the desired tradeoff between code size and conversion precision: - BASIC method is the smallest code footprint - APPROX method uses an iterative method to approximate the exact representation, which is a bit slower but but does not have a big impact on code size. It provides `repr` reversibility on >99.8% of the cases in double precision, and on >98.5% in single precision (except with REPR_C, where reversibility is 100% as the last two bits are not taken into account). - EXACT method uses higher-precision floats during conversion, which provides perfect results but has a higher impact on code size. It is faster than APPROX method, and faster than the CPython equivalent implementation. It is however not available on all compilers when using FLOAT_IMPL_DOUBLE. Here is the table comparing the impact of the three conversion methods on code footprint on PYBV10 (using single-precision floats) and reversibility rate for both single-precision and double-precision floats. The table includes current situation as a baseline for the comparison: PYBV10 REPR_C FLOAT DOUBLE current = 364688 12.9% 27.6% 37.9% basic = 364812 85.6% 60.5% 85.7% approx = 365080 100.0% 98.5% 99.8% exact = 366408 100.0% 100.0% 100.0% Signed-off-by: Yoctopuce dev <dev@yoctopuce.com>
2017-07-31all: Use the name MicroPython consistently in commentsAlexander Steffen
There were several different spellings of MicroPython present in comments, when there should be only one.
2017-07-18all: Unify header guard usage.Alexander Steffen
The code conventions suggest using header guards, but do not define how those should look like and instead point to existing files. However, not all existing files follow the same scheme, sometimes omitting header guards altogether, sometimes using non-standard names, making it easy to accidentally pick a "wrong" example. This commit ensures that all header files of the MicroPython project (that were not simply copied from somewhere else) follow the same pattern, that was already present in the majority of files, especially in the py folder. The rules are as follows. Naming convention: * start with the words MICROPY_INCLUDED * contain the full path to the file * replace special characters with _ In addition, there are no empty lines before #ifndef, between #ifndef and one empty line before #endif. #endif is followed by a comment containing the name of the guard macro. py/grammar.h cannot use header guards by design, since it has to be included multiple times in a single C file. Several other files also do not need header guards as they are only used internally and guaranteed to be included only once: * MICROPY_MPHALPORT_H * mpconfigboard.h * mpconfigport.h * mpthreadport.h * pin_defs_*.h * qstrdefs*.h
2015-05-17py: Implement mp_format_float for doubles and use where appropriatestijn
This allows using (almost) the same code for printing floats everywhere, removes the dependency on sprintf and uses just snprintf and applies an msvc-specific fix for snprintf in a single place so nan/inf are now printed correctly.
2015-01-01py: Move to guarded includes, everywhere in py/ core.Damien George
Addresses issue #1022.
2014-05-03Add license header to (almost) all files.Damien George
Blanket wide to all .c and .h files. Some files originating from ST are difficult to deal with (license wise) so it was left out of those. Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
2014-03-10Rename formatfloat file; remove MICROPY_ENABLE_FLOAT from mpconfigport.h.Damien George
MICROPY_ENABLE_FLOAT is automatically set in mpconfig.h if MICROPY_FLOAT_IMPL is set to a non-zero value.