0001154: string_of_float loosing precision

Notes
(0000124) administrator (administrator) 2002-06-27 10:50	string_of_float is just printf "%.12g", hence limited precision. An "exact" conversion would be nice but isn't provided by the C standard library.

(0006754) doligez (manager) 2012-01-20 14:26	At this point, string_of_float is a quick-and-dirty function. If you need more precision, you should use printf and specify the number of digits. Maybe someday, someone will implement [Clinger1990] and [Steele1990] for OCaml and submit a patch, but don't hold your breath. @inproceedings{Clinger1990, author = {Clinger, William D.}, title = {How to read floating point numbers accurately}, booktitle = {Proceedings of the ACM SIGPLAN 1990 conference on Programming language design and implementation}, series = {PLDI '90}, year = {1990}, isbn = {0-89791-364-7}, location = {White Plains, New York, United States}, pages = {92--101}, numpages = {10}, url = {http://doi.acm.org/10.1145/93542.93557}, [^] doi = {http://doi.acm.org/10.1145/93542.93557}, [^] acmid = {93557}, publisher = {ACM}, address = {New York, NY, USA}, } @inproceedings{Steele1990, author = {Steele,Jr., Guy L. and White, Jon L.}, title = {How to print floating-point numbers accurately}, booktitle = {Proceedings of the ACM SIGPLAN 1990 conference on Programming language design and implementation}, series = {PLDI '90}, year = {1990}, isbn = {0-89791-364-7}, location = {White Plains, New York, United States}, pages = {112--126}, numpages = {15}, url = {http://doi.acm.org/10.1145/93542.93559}, [^] doi = {http://doi.acm.org/10.1145/93542.93559}, [^] acmid = {93559}, publisher = {ACM}, address = {New York, NY, USA}, }

(0007413) dbuenzli (reporter) 2012-05-04 16:15	Somehow I still think it would be nice if : (float_of_string (string_of_float i)) = i could be true for all the integers i that can be represented exactly in OCaml's float value. These integers are in the interval [-2^53;2^53]. This could be achieved by using "%.16g", i.e. is true for : (float_of_string (Printf.sprintf "%.16g" i)) Best, Daniel

Issue History
Date Modified	Username	Field	Change
2005-11-18 10:13	administrator	New Issue
2012-01-20 14:16	doligez	Relationship added	related to 0004345
2012-01-20 14:26	doligez	Note Added: 0006754
2012-01-20 14:26	doligez	Status	acknowledged => resolved
2012-01-20 14:26	doligez	Resolution	open => suspended
2012-01-20 14:26	doligez	Description Updated	View Revisions
2012-01-26 18:30	doligez	Relationship added	related to 0001829
2012-05-04 16:15	dbuenzli	Note Added: 0007413