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[Help-smalltalk] BUG gst2.2: Fraction hash
From: |
nicolas cellier |
Subject: |
[Help-smalltalk] BUG gst2.2: Fraction hash |
Date: |
Sat, 27 Jan 2007 03:47:38 +0100 |
User-agent: |
Thunderbird 1.5.0.4 (X11/20060516) |
Fraction>>hash does inline Fraction as Float with a different algorithm
than Fraction>>asFloat...
Consequently, when numerator and/or denominator grows big, a bug appears:
| xFrac xFloat |
xFrac := 9/10 raisedToInteger: 400.
xFloat = xFrac asFloatD.
xFrac hash = xFloat hash
xFrac and xFloat will answer true to equality (this is arguable, because
only their floating point approximation are equal, not their
exactFraction representation, but this is another thread).
But their hash code will not be equal... Bad thing for Set and
Dictionary mixing Fraction and Float...
Nicolas Cellier
- [Help-smalltalk] BUG gst2.2: Fraction hash,
nicolas cellier <=