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Faster conversion between Rational and Double/Float

The proposal for the new implementation of fromRational and toRational was discussed (very briefly) here. Supported by Simon Peyton Jones and (off list) Jason Dagit. No dissent.

The old implementation of toRational and fromRational for Double and Float was extremely slow. Exploiting the representation of the involved types allows an order of magnitude speedup. In particular a fast base-2 logarithm is needed, this has to be implemented in the integer-gmp resp. integer-simple packages, therefore three patches are needed, for base and each of the integer packages.

Trac metadata
Trac field Value
Version 7.0.3
Type Task
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component libraries (other)
Test case
Differential revisions
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