[squeak-dev] The Trunk: Kernel-nice.1460.mcz

commits at source.squeak.org commits at source.squeak.org
Sun Apr 24 14:41:03 UTC 2022

Nicolas Cellier uploaded a new version of Kernel to project The Trunk:

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

Name: Kernel-nice.1460
Author: nice
Time: 24 April 2022, 4:40:46.56674 pm
UUID: c06981bc-7eba-4a8e-a388-658d43b49ec8
Ancestors: Kernel-nice.1459

Oups fixup (2 i sqrt), not enough tests...
Sorry for the noise.

=============== Diff against Kernel-nice.1459 ===============

Item was changed:
  ----- Method: Complex>>sqrt (in category 'mathematical functions') -----
+ 	"Return the square root of the receiver with a positive real part.
+ 	This is the same as (Complex abs: self abs sqrt arg: self arg / 2).
- 	"Return the square root of the receiver with a positive imaginary part.
  	Implementation notes:
  	the formulation used ensure a protection against floating point overflow/underflow.
  	it also result in a reasonable precision (around 3 ulp).
  	It is inspired by following reference, except that it uses pre-scaling rather than eception handling:
  	Implementing Complex Elementary Function Using Exception Handling
  	ACM Transactions on Mathematical Software - October 1994
  	Ping Tang and 3 other authors"
  	| x y r s t scale |
  	real isZero
+ 			[t := imaginary abs sqrt / 2 sqrt.
- 			[t := imaginary abs sqrt.
  			^self class real: t imaginary: (imaginary copySignTo: t)].
  	scale := real abs max: imaginary abs.
  	x := real / scale.
  	y := imaginary / scale.
  	r := (x squared + y squared) sqrt.
  	s := scale sqrt.
  	t := (r + x abs * 2) sqrt.
  	^real > 0
  		ifTrue: [self class real: t * s / 2 imaginary: y * s / t]
  		ifFalse: [self class real: y abs * s / t imaginary: (y copySignTo: t * s / 2)]!

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