Opened 5 years ago

Closed 5 years ago

#370 closed defect (fixed)

Log of exact and inexact zero

Reported by: cowan Owned by: cowan
Priority: major Milestone:
Component: WG1 - Core Keywords:

Description (last modified by cowan)

R5RS and draft 6 of R7RS don't say what (log 0.0) and (log 0) return. R6RS requires -inf.0 and an exception respectively. The proposal is to say that (log 0.0) returns -inf.0 on systems that have +inf.0, and that (log 0) is an error.

In Racket, Gambit, Chicken (with the numbers egg), Guile, Chibi, Chez, Ikarus/Vicare, Larceny, Ypsilon, Mosh, IronScheme, STklos, Spark, (log 0.0) returns -inf.0 and (log 0) raises an exception.

Gauche, MIT, Chicken (without the numbers egg), Bigloo, Scheme48/scsh, Kawa, SISC, SCM, NexJ, KSi, RScheme, XLisp, Rep, VX, SXM, Inlab return -inf.0 in both cases.

Elk, UMB, Oaklisp raise an exception in both cases.

Scheme 7 returns the wrong answer in both cases.

SigScheme, Shoe, TinyScheme, Dream, BDC, Owl Lisp don't support log.

Scheme 9 apparently goes into an infinite loop in both cases.

Change History (4)

comment:1 Changed 5 years ago by cowan

  • Description modified (diff)

comment:2 Changed 5 years ago by cowan

  • Status changed from new to decided

WG1 voted to adopt this proposal.

comment:3 Changed 5 years ago by cowan

  • Owner changed from alexshinn to cowan
  • Status changed from decided to writing

comment:4 Changed 5 years ago by cowan

  • Resolution set to fixed
  • Status changed from writing to closed
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