The Trunk: Kernel-nice.691.mcz

Nicolas Cellier uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-nice.691.mcz

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

Name: Kernel-nice.691
Author: nice
Time: 22 May 2012, 10:14:29.897 pm
UUID: f69b524f-83bb-4ef0-b084-e7a96dd5d33e
Ancestors: Kernel-eem.690, Kernel-nice.690

Grace period is over, publish and merge the changes for printing Floating point with fixed precision.

=============== Diff against Kernel-eem.690 ===============

Item was added:
+ ----- Method: Float>>absPrintExactlyOn:base:decimalPlaces:showTrailingFractionalZeros: (in category 'printing') -----
+ absPrintExactlyOn: aStream base: base decimalPlaces: placesDesired showTrailingFractionalZeros: showtrailingZeros
+ "Print my value on a stream in the given base with fixed number of digits after floating point.
+ When placesDesired are beyond Float precision, zeroes are appended.
+ When showtrailingZeros is false, the trailing zeroes after decimal point will be omitted.
+ If all fractional digits are zeros, the decimal point is omitted too.
+ Assumes that my value is strictly positive; negative numbers, zero, and NaNs have already been handled elsewhere.
+ Based upon the algorithm outlined in:
+ Robert G. Burger and R. Kent Dybvig
+ Printing Floating Point Numbers Quickly and Accurately
+ ACM SIGPLAN 1996 Conference on Programming Language Design and Implementation
+ June 1996.."
+
+ | significand exp baseExpEstimate r s mPlus mMinus scale roundingLowIncludesLimits roundingHighIncludesLimits d tc1 tc2 decPointCount slowbit shead delta |
+ self isInfinite ifTrue: [aStream nextPutAll: 'Infinity'. ^ self].
+ significand := self significandAsInteger.
+ exp := (self exponent - 52) max: MinValLogBase2.
+ exp >= 0
+ ifTrue:
+ [significand ~= 16r10000000000000
+ ifTrue:
+ [r := significand bitShift: 1 + exp.
+ s := 2.
+ mPlus := mMinus := 1 bitShift: exp]
+ ifFalse:
+ [r := significand bitShift: 2 + exp.
+ s := 4.
+ mPlus := 2 * (mMinus := 1 bitShift: exp)]]
+ ifFalse:
+ [(exp = MinValLogBase2 or: [significand ~= 16r10000000000000])
+ ifTrue:
+ [r := significand bitShift: 1.
+ s := 1 bitShift: 1 - exp.
+ mPlus := mMinus := 1]
+ ifFalse:
+ [r := significand bitShift: 2.
+ s := 1 bitShift: 2 - exp.
+ mPlus := 2.
+ mMinus := 1]].
+ delta := s / 2 / (base raisedTo: placesDesired).
+ roundingLowIncludesLimits :=  (mMinus < delta and: [mMinus := delta. true]) or: [significand even].
+ roundingHighIncludesLimits := (mPlus < delta and: [mPlus := delta. true]) or: [significand even].
+ baseExpEstimate := (self exponent * base asFloat reciprocalLogBase2 - 1.0e-10) ceiling.
+ baseExpEstimate >= 0
+ ifTrue: [s := s * (base raisedToInteger: baseExpEstimate)]
+ ifFalse:
+ [scale := base raisedToInteger: baseExpEstimate negated.
+ r := r * scale.
+ mPlus := mPlus * scale.
+ mMinus := mMinus * scale].
+ ((r + mPlus >= s) and: [roundingHighIncludesLimits or: [r + mPlus > s]])
+ ifTrue: [baseExpEstimate := baseExpEstimate + 1]
+ ifFalse:
+ [r := r * base.
+ mPlus := mPlus * base.
+ mMinus := mMinus * base].
+ decPointCount := baseExpEstimate.
+ baseExpEstimate <= 0
+ ifTrue:
+ [placesDesired + baseExpEstimate <= 0
+ ifTrue:
+ [aStream nextPut: $0.
+ (showtrailingZeros and: [placesDesired > 0]) ifTrue: [aStream nextPut: $.; nextPutAll: (String new: placesDesired withAll: $0)].
+ ^self].
+ aStream nextPutAll: '0.'; nextPutAll: (String new: 0 - baseExpEstimate withAll: $0)].
+ slowbit := 1 - s lowBit .
+ shead := s bitShift: slowbit.
+ [d := (r bitShift: slowbit) // shead.
+ r := r - (d * s).
+ (tc1 := (r <= mMinus) and: [roundingLowIncludesLimits or: [r < mMinus]]) |
+ (tc2 := (r + mPlus >= s) and: [roundingHighIncludesLimits or: [r + mPlus > s]])] whileFalse:
+ [aStream nextPut: (Character digitValue: d).
+ r := r * base.
+ mPlus := mPlus * base.
+ mMinus := mMinus * base.
+ (decPointCount := decPointCount - 1) = 0 ifTrue: [aStream nextPut: $.]].
+ tc2 ifTrue:
+ [(tc1 not or: [r * 2 >= s]) ifTrue: [d := d + 1]].
+ aStream nextPut: (Character digitValue: d).
+ decPointCount > 0
+ ifTrue:
+ [decPointCount - 1 to: 1 by: -1 do: [:i | aStream nextPut: $0].
+ (showtrailingZeros and: [placesDesired > 0]) ifTrue: [aStream nextPut: $.; nextPutAll: (String new: placesDesired withAll: $0)]]
+ ifFalse:
+ [(showtrailingZeros and: [placesDesired + decPointCount > 1]) ifTrue: [aStream nextPutAll: (String new: placesDesired + decPointCount - 1 withAll: $0)]].!

Item was changed:
+ ----- Method: Float>>absPrintOn:base:digitCount: (in category 'printing') -----
- ----- Method: Float>>absPrintOn:base:digitCount: (in category 'private') -----
  absPrintOn: aStream base: base digitCount: digitCount
  "Print me in the given base, using digitCount significant figures."
 
  | fuzz x exp q fBase scale logScale xi |
  self isInfinite ifTrue: [^ aStream nextPutAll: 'Inf'].
  fBase := base asFloat.
  "x is myself normalized to [1.0, fBase), exp is my exponent"
  exp :=
  self < 1.0
  ifTrue: [self reciprocalFloorLog: fBase]
  ifFalse: [self floorLog: fBase].
  scale := 1.0.
  logScale := 0.
  [(x := fBase raisedTo: (exp + logScale)) = 0]
  whileTrue:
  [scale := scale * fBase.
  logScale := logScale + 1].
  x := self * scale / x.
  fuzz := fBase raisedTo: 1 - digitCount.
  "round the last digit to be printed"
  x := 0.5 * fuzz + x.
  x >= fBase
  ifTrue:
  ["check if rounding has unnormalized x"
  x := x / fBase.
  exp := exp + 1].
  (exp < 6 and: [exp > -4])
  ifTrue:
  ["decimal notation"
  q := 0.
  exp < 0 ifTrue: [1 to: 1 - exp do: [:i | aStream nextPut: ('0.0000'
  at: i)]]]
  ifFalse:
  ["scientific notation"
  q := exp.
  exp := 0].
  [x >= fuzz]
  whileTrue:
  ["use fuzz to track significance"
  xi := x asInteger.
  aStream nextPut: (Character digitValue: xi).
  x := x - xi asFloat * fBase.
  fuzz := fuzz * fBase.
  exp := exp - 1.
  exp = -1 ifTrue: [aStream nextPut: $.]].
  [exp >= -1]
  whileTrue:
  [aStream nextPut: $0.
  exp := exp - 1.
  exp = -1 ifTrue: [aStream nextPut: $.]].
  q ~= 0
  ifTrue:
  [aStream nextPut: $e.
  q printOn: aStream]!

Item was added:
+ ----- Method: Float>>printOn:maxDecimalPlaces: (in category 'printing') -----
+ printOn: aStream maxDecimalPlaces: placesDesired
+ "Refine super implementation in order to avoid any rounding error caused by rounded or roundTo:"
+
+ self isFinite ifFalse: [^self printOn: aStream].
+ self > 0.0
+ ifTrue: [self absPrintExactlyOn: aStream base: 10 decimalPlaces: placesDesired showTrailingFractionalZeros: false]
+ ifFalse:
+ [self sign = -1
+ ifTrue: [aStream nextPutAll: '-'].
+ self = 0.0
+ ifTrue: [aStream nextPutAll: '0.0']
+ ifFalse: [self absPrintExactlyOn: aStream base: 10 decimalPlaces: placesDesired showTrailingFractionalZeros: false]]!

Item was added:
+ ----- Method: Float>>printOn:showingDecimalPlaces: (in category 'printing') -----
+ printOn: aStream showingDecimalPlaces: placesDesired
+ "Refine super implementation in order to avoid any rounding error caused by rounded or roundTo:"
+
+ self isFinite ifFalse: [^self printOn: aStream].
+ self > 0.0
+ ifTrue: [self absPrintExactlyOn: aStream base: 10 decimalPlaces: placesDesired showTrailingFractionalZeros: true]
+ ifFalse:
+ [self sign = -1
+ ifTrue: [aStream nextPutAll: '-'].
+ self = 0.0
+ ifTrue: [aStream nextPutAll: '0.0']
+ ifFalse: [self absPrintExactlyOn: aStream base: 10 decimalPlaces: placesDesired showTrailingFractionalZeros: true]]!

Item was removed:
- ----- Method: Float>>printShowingDecimalPlaces: (in category 'printing') -----
- printShowingDecimalPlaces: placesDesired
- "This implementation avoids any rounding error caused by rounded or roundTo:"
-
- self isFinite ifFalse: [^self printString].
- ^self asTrueFraction printShowingDecimalPlaces: placesDesired!

On Tue, May 22, 2012 at 08:14:50PM +0000, [hidden email] wrote:
+1

Thanks!

Dave