Lisp Knowledgebase
Title: Floats are read with single precision by default
ID: 17053
| Product: LispWorks Version: All OS: All | |
| Description: Floating point numbers are read by default as single-float values. This is the default Common Lisp behavior (see http://www.lispworks.com/documentation/HyperSpec/Body/v_rd_def.htm). The single-float type has only 23 bits in the mantissa, resulting in apparent loss of precision for some numbers such as (- 605113171.148 605113170.148) => 0.0 However, if you force these numbers to be read as double-float, then the form returns the expected result, for example: (- 605113171.148d0 605113170.148d0) => 1.0D0 Note: LispWorks 4 on Windows and Linux has a different default behavior. See other article for details. | |
| See Also: (link) Workaround: Patch: | |
| Hardware:N/A | |
| Summary: | |
| Bug#: | |
| Patch Enhancement#: | |
| Reported: | |