2011/10/29 commits@source.squeak.org:

Nicolas Cellier uploaded a new version of Kernel to project The Trunk: http://source.squeak.org/trunk/Kernel-nice.646.mcz

==================== Summary ====================

Name: Kernel-nice.646 Author: nice Time: 29 October 2011, 3:25:43.994 pm UUID: cd46101c-40a4-49fd-b358-a8d0c555810f Ancestors: Kernel-nice.645

There might be a best inexact square root approximation than Float infinity to some LargePositiveInteger in the range (1<<54-1<<970 to: 1<<54-1<<1994)

I mean a better approximation... But it should effectively be the best.

=============== Diff against Kernel-nice.645 ===============

Item was changed:  ----- Method: Integer>>sqrt (in category 'mathematical functions') -----  sqrt        "Answer the square root of the receiver."

| selfAsFloat floatResult guess |        selfAsFloat := self asFloat.        floatResult := selfAsFloat sqrt.

floatResult isInfinite ifFalse: [                guess := floatResult truncated.

"If got an exact answer, answer it. Otherwise answer float approximate answer."                guess squared = self                        ifTrue: [ ^ guess ]].

"In this case, maybe it failed because we are such a big integer that the Float method becomes        inexact, even if we are a whole square number. So, try the slower but more general method"        selfAsFloat >= Float maxExactInteger asFloat squared                ifTrue: [                        guess := self sqrtFloor.                        guess squared = self ifTrue: [

• ^guess ].
• "Nothing else can be done. No exact answer means answer must be a Float.
• Answer the best we have which is the rounded sqrt."
• guess := (self * 4) sqrtFloor.
• ^(guess // 2 + (guess \ 2)) asFloat].

• ^guess ]].

"We need an approximate result"        ^floatResult!

Item was changed:  ----- Method: LargePositiveInteger>>sqrt (in category 'mathematical functions') -----  sqrt        "If we know for sure no exact solution exists, then just answer the cheap float approximation without wasting time."

• | selfAsFloat |
• self mightBeASquare
• ifFalse:
• [selfAsFloat := self asFloat.
• selfAsFloat isFinite ifTrue: [^self asFloat sqrt ]].

• self mightBeASquare ifFalse: [
• ^self asFloat sqrt ].

• "If some exact solution might exist, or self asFloat isInfinite, call potentially expensive super"

• "If some exact solution might exist,  call potentially expensive super"

^super sqrt!