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Bug #776

FloatStr prints a NUL character

Added by John Abbott almost 9 years ago. Updated over 8 years ago.

Status:
Closed
Priority:
Normal
Assignee:
John Abbott
Category:
Maths Bugs
Target version:
CoCoALib-0.99540 Feb 2016
Start date:
15 Sep 2015
Due date:
% Done:

100%

Estimated time:
Spent time:
2.10 h

Description

FloatStr prints out a NUL character in some cases.

J := 38478521676166483490305685030818526171181904643421577733382705346571894686085840002453315602443444444401/38478521676166483605741250097796497856523182881313912761668255277583712667477744737709244389536050430475222646784;
FloatStr(J,19);
9.99999999999999997

History

#1 Updated by John Abbott almost 9 years ago

JAA is sure that smaller examples exist (but too tired to search now).

NOTE it seems that redmine does not like having NUL chars pasted into it... the example output above is truncated at the NUL

#2 Updated by John Abbott almost 9 years ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 10

The problem seems to be ILogBase(...,10) giving a wrong result: it gives -9 instead of -10.

#3 Updated by John Abbott almost 9 years ago

  • Status changed from In Progress to Feedback
  • % Done changed from 10 to 90

The bug was some overly delicate bug in ILogBase implemented in BigRat.C; I had forgotten to allow for possible fp rounding :-(

All seems OK now; the new code is less "slick" but shorter and apparently correct.

#4 Updated by John Abbott over 8 years ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

No problems have surfaced in the last 5 months, so closing.

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