[squeak-dev] Float differences

Sven Van Caekenberghe sven at beta9.be
Wed Apr 25 20:20:20 UTC 2012


The following code

((-10 to: 10) collect: [ :each | each * Float pi ])
((((-10 to: 10) collect: [ :each | each * Float pi ]) 
	collect: [ :each | each asString])
		collect: [ :each | Float readFrom: each ])

returns true on Pharo 1.4 and false on Squeak 4.3
Some of the Floats in the array compare equal, some not.

Similary, (10 raisedTo: -100) asFloat

prints as '1.0e-100' in Pharo and as ' 9.99999999999999e-101' in Squeak.

I know that comparing Floats on equality is often dangerous and that #closeTo: is better.
But I would like to understand how there could be such a difference between the two. 

Nicolas ?



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