From: Todd Kushner Date: 2011-09-08T00:04:50+09:00 Subject: [ruby-core:39342] [Ruby 1.9 - Bug #5294][Open] to_f does not convert floating point number the same as Fortran Issue #5294 has been reported by Todd Kushner. ---------------------------------------- Bug #5294: to_f does not convert floating point number the same as Fortran http://redmine.ruby-lang.org/issues/5294 Author: Todd Kushner Status: Open Priority: Normal Assignee: Category: Target version: ruby -v: 1.9.2p180 (2011-02-18) [i386-mingw32] We were converting some Fortran programs to Ruby, and found the following floating point number format did not convert as Fortran does on input, i.e., on: '[+-]nn.E[+-]nn' the exponent is ignored by to_f, but not by Fortran: string: '9.E+20 ' float: 9.0000000000000000000000000 string: '+9.E+20 ' float: 9.0000000000000000000000000 string: '-9.E+20 ' float: -9.0000000000000000000000000 string: '9.E20 ' float: 9.0000000000000000000000000 string: '+9.E20 ' float: 9.0000000000000000000000000 string: '-9.E20 ' float: -9.0000000000000000000000000 string: '9.E-20 ' float: 9.0000000000000000000000000 string: '+9.E-20 ' float: 9.0000000000000000000000000 string: '-9.E-20 ' float: -9.0000000000000000000000000 Listed below, we found all other variations we could think of seemed to work properly: string: '0.9E+21 ' float: 900000000000000000000.0000000000000000000000000 string: '+0.9E+21 ' float: 900000000000000000000.0000000000000000000000000 string: '-0.9E+21 ' float: -900000000000000000000.0000000000000000000000000 string: '.9E+21 ' float: 900000000000000000000.0000000000000000000000000 string: '+.9E+21 ' float: 900000000000000000000.0000000000000000000000000 string: '-.9E+21 ' float: -900000000000000000000.0000000000000000000000000 string: '9E+20 ' float: 900000000000000000000.0000000000000000000000000 string: '+9E+20 ' float: 900000000000000000000.0000000000000000000000000 string: '-9E+20 ' float: -900000000000000000000.0000000000000000000000000 string: '9.0E+20 ' float: 900000000000000000000.0000000000000000000000000 string: '+9.0E+20 ' float: 900000000000000000000.0000000000000000000000000 string: '-9.0E+20 ' float: -900000000000000000000.0000000000000000000000000 string: '0.9E21 ' float: 900000000000000000000.0000000000000000000000000 string: '+0.9E21 ' float: 900000000000000000000.0000000000000000000000000 string: '-0.9E21 ' float: -900000000000000000000.0000000000000000000000000 string: '.9E21 ' float: 900000000000000000000.0000000000000000000000000 string: '+.9E21 ' float: 900000000000000000000.0000000000000000000000000 string: '-.9E21 ' float: -900000000000000000000.0000000000000000000000000 string: '9E20 ' float: 900000000000000000000.0000000000000000000000000 string: '+9E20 ' float: 900000000000000000000.0000000000000000000000000 string: '-9E20 ' float: -900000000000000000000.0000000000000000000000000 string: '9.0E20 ' float: 900000000000000000000.0000000000000000000000000 string: '+9.0E20 ' float: 900000000000000000000.0000000000000000000000000 string: '-9.0E20 ' float: -900000000000000000000.0000000000000000000000000 string: '0.9E-19 ' float: 0.0000000000000000000900000 string: '+0.9E-19 ' float: 0.0000000000000000000900000 string: '-0.9E-19 ' float: -0.0000000000000000000900000 string: '.9E-19 ' float: 0.0000000000000000000900000 string: '+.9E-19 ' float: 0.0000000000000000000900000 string: '-.9E-19 ' float: -0.0000000000000000000900000 string: '9E-20 ' float: 0.0000000000000000000900000 string: '+9E-20 ' float: 0.0000000000000000000900000 string: '-9E-20 ' float: -0.0000000000000000000900000 string: '9.0E-20 ' float: 0.0000000000000000000900000 string: '+9.0E-20 ' float: 0.0000000000000000000900000 string: '-9.0E-20 ' float: -0.0000000000000000000900000 Thanks! Todd Kushner Jeppesen todd.kushner@jeppesen.com -- http://redmine.ruby-lang.org