Compute the double value nearest preferred decimal result

Question

Let N(x) be the value of the decimal numeral with the fewest significant digits such that x is the double value nearest the value of the numeral.

Given

Answer 1

You could also inquire in Smalltalk Pharo 2.0 where your request translates:

^(b asMinimalDecimalFraction - a asMinimalDecimalFraction) asFloat

Code could be found as attachment to issue 4957 at code.google.com/p/pharo/issues - alas, dead link, and the new bugtracker requires a login...

https://pharo.fogbugz.com/f/cases/5000/Let-asScaledDecimal-use-the-right-number-of-decimals

source code is also on github, currently:

https://github.com/pharo-project/pharo-core/blob/6.0/Kernel.package/Float.class/instance/printing/asMinimalDecimalFraction.st

The algorithm is based on:

Robert G. Burger and R. Kent Dybvig
Printing Floating Point Numbers Quickly and Accurately
ACM SIGPLAN 1996 Conference on Programming Language Design and Implementation
June 1996.
http://www.cs.indiana.edu/~dyb/pubs/FP-Printing-PLDI96.pdf