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Some bugs I ran into while working on hashing

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Andres Valloud-4

Some bugs I ran into while working on hashing

Hello, are these problems known? I am using the latest RC build.

* Create changeset X. Touch method Foo>>bar. Create changeset Y.
Touch method Foo>>bar again. Fileout changeset X. The fileout has the
code for changeset Y.

* Delete the first ! in a changeset with a preamble. Try to load it
from the file tool. You get a syntax error. However, the progress bar
does not go away. Is the file handle released?

* Integer>>isPrime should not be probabilistic. Suggestion: rename it
to Integer>>isMostLikelyPrime or something similar. Implement a
deterministic prime check for isPrime (even if it is slow --- users then
can decide whether they want a deterministic or probabilistic answer).
Here's a rough sketch of Integer>>isPrime:

isPrime

| guess guessSquared delta selfSqrtFloor |
self <= 1 ifTrue: [^self error: 'operation undefined'].
self even ifTrue: [^self = 2].
guess := 1 bitShift: self highBit + 1 // 2.
[
guessSquared := guess * guess.
delta := guessSquared - self // (guess bitShift: 1).
delta = 0
] whileFalse: [guess := guess - delta].
guessSquared = self ifFalse: [guess := guess - 1].
selfSqrtFloor := guess.
3 to: selfSqrtFloor by: 2 do: [:each | self \\ each = 0 ifTrue:
[^false]].
^true

Also, the above code can be used to implement sqrtFloor and sqrtRounded
in Integer. I am sure Nicolas Cellier remembers this :). Finally, I'm
not sure that isPrime should fail with "undefined operation" if the
receiver is <= 1. 1 is certainly not prime. Primes must be positive,
so zero and the negatives could just answer false. ???...

* Open an inspector on e.g.: Smalltalk. In the code pane, type:

self keys inject: Set new into: [:t :x | t add: x class; yourself]

Using the mouse, select the expression, and inspect the result using the
right button menu item. The result comes up. However, the inspector on
Smalltalk experiences a failure in one of its panes because lines is nil
in MultiNewParagraph(NewParagraph)>>fastFindFirstLineSuchThat:

Andres.

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Stéphane Ducasse

Re: Some bugs I ran into while working on hashing

thanks andres
can you open bug entries?

> Hello, are these problems known? I am using the latest RC build.
>
> * Create changeset X. Touch method Foo>>bar. Create changeset Y.
> Touch method Foo>>bar again. Fileout changeset X. The fileout has
> the
> code for changeset Y.

It has always been like that in squeak since years. in Squeak cs do
not record actual change
but just that something changed.

> * Delete the first ! in a changeset with a preamble. Try to load it
> from the file tool. You get a syntax error. However, the progress
> bar
> does not go away. Is the file handle released?
>
> * Integer>>isPrime should not be probabilistic. Suggestion: rename it
> to Integer>>isMostLikelyPrime or something similar. Implement a
> deterministic prime check for isPrime (even if it is slow --- users
> then
> can decide whether they want a deterministic or probabilistic answer).
> Here's a rough sketch of Integer>>isPrime:
>
> isPrime
>
> | guess guessSquared delta selfSqrtFloor |
> self <= 1 ifTrue: [^self error: 'operation undefined'].
> self even ifTrue: [^self = 2].
> guess := 1 bitShift: self highBit + 1 // 2.
> [
> guessSquared := guess * guess.
> delta := guessSquared - self // (guess bitShift: 1).
> delta = 0
> ] whileFalse: [guess := guess - delta].
> guessSquared = self ifFalse: [guess := guess - 1].
> selfSqrtFloor := guess.
> 3 to: selfSqrtFloor by: 2 do: [:each | self \\ each = 0 ifTrue:
> [^false]].
> ^true
>
>
> Also, the above code can be used to implement sqrtFloor and
> sqrtRounded
> in Integer. I am sure Nicolas Cellier remembers this :). Finally,
> I'm
> not sure that isPrime should fail with "undefined operation" if the
> receiver is <= 1. 1 is certainly not prime. Primes must be positive,
> so zero and the negatives could just answer false. ???...
>
> * Open an inspector on e.g.: Smalltalk. In the code pane, type:
>
> self keys inject: Set new into: [:t :x | t add: x class; yourself]
>
> Using the mouse, select the expression, and inspect the result using
> the
> right button menu item. The result comes up. However, the
> inspector on
> Smalltalk experiences a failure in one of its panes because lines is
> nil
> in MultiNewParagraph(NewParagraph)>>fastFindFirstLineSuchThat:
>
> Andres.
>
> _______________________________________________
> Pharo-project mailing list
> [hidden email]
> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

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Nicolas Cellier

Re: Some bugs I ran into while working on hashing

In reply to this post by Andres Valloud-4

2009/10/25 Andres Valloud <[hidden email]>:

>
> isPrime
>
> | guess guessSquared delta selfSqrtFloor |
> self <= 1 ifTrue: [^self error: 'operation undefined'].
> self even ifTrue: [^self = 2].
> guess := 1 bitShift: self highBit + 1 // 2.
> [
> guessSquared := guess * guess.
> delta := guessSquared - self // (guess bitShift: 1).
> delta = 0
> ] whileFalse: [guess := guess - delta].
> guessSquared = self ifFalse: [guess := guess - 1].
> selfSqrtFloor := guess.
> 3 to: selfSqrtFloor by: 2 do: [:each | self \\ each = 0 ifTrue:
> [^false]].
> ^true
>
>
> Also, the above code can be used to implement sqrtFloor and sqrtRounded
> in Integer. I am sure Nicolas Cellier remembers this :).

If http://bugs.squeak.org were not down, I would even provide a link
with these enhancements

>
> Andres.
>
> _______________________________________________
> Pharo-project mailing list
> [hidden email]
> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
>

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Nicolas Cellier

Re: Some bugs I ran into while working on hashing

2009/10/25 Nicolas Cellier <[hidden email]>:

> 2009/10/25 Andres Valloud <[hidden email]>:
>>
>> isPrime
>>
>> | guess guessSquared delta selfSqrtFloor |
>> self <= 1 ifTrue: [^self error: 'operation undefined'].
>> self even ifTrue: [^self = 2].
>> guess := 1 bitShift: self highBit + 1 // 2.
>> [
>> guessSquared := guess * guess.
>> delta := guessSquared - self // (guess bitShift: 1).
>> delta = 0
>> ] whileFalse: [guess := guess - delta].
>> guessSquared = self ifFalse: [guess := guess - 1].
>> selfSqrtFloor := guess.
>> 3 to: selfSqrtFloor by: 2 do: [:each | self \\ each = 0 ifTrue:
>> [^false]].
>> ^true
>>
>>
>> Also, the above code can be used to implement sqrtFloor and sqrtRounded
>> in Integer. I am sure Nicolas Cellier remembers this :).
>
> If http://bugs.squeak.org were not down, I would even provide a link
> with these enhancements
>

google says it should be http://www.google.fr/bugs.squeak.org/view.php?id=7099.
Or go to the source
http://blogten.blogspot.com/2008/06/drove-to-reno-today.html
http://blogten.blogspot.com/2008/06/update-on-sqrtrounded.html

>>
>> Andres.
>>
>> _______________________________________________
>> Pharo-project mailing list
>> [hidden email]
>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
>>
>

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Stéphane Ducasse

Re: Some bugs I ran into while working on hashing

nicolas if you produce a slice I will integrate them.
For now I'm focusing on emptying the pending stack of fixed items

Stef

On Oct 25, 2009, at 4:53 PM, Nicolas Cellier wrote:

> 2009/10/25 Nicolas Cellier <[hidden email]>:
>> 2009/10/25 Andres Valloud <[hidden email]>:
>>>
>>> isPrime
>>>
>>> | guess guessSquared delta selfSqrtFloor |
>>> self <= 1 ifTrue: [^self error: 'operation undefined'].
>>> self even ifTrue: [^self = 2].
>>> guess := 1 bitShift: self highBit + 1 // 2.
>>> [
>>> guessSquared := guess * guess.
>>> delta := guessSquared - self // (guess bitShift: 1).
>>> delta = 0
>>> ] whileFalse: [guess := guess - delta].
>>> guessSquared = self ifFalse: [guess := guess - 1].
>>> selfSqrtFloor := guess.
>>> 3 to: selfSqrtFloor by: 2 do: [:each | self \\ each = 0 ifTrue:
>>> [^false]].
>>> ^true
>>>
>>>
>>> Also, the above code can be used to implement sqrtFloor and
>>> sqrtRounded
>>> in Integer. I am sure Nicolas Cellier remembers this :).
>>
>> If http://bugs.squeak.org were not down, I would even provide a link
>> with these enhancements
>>
>
> google says it should be http://www.google.fr/bugs.squeak.org/view.php?id=7099
> .
> Or go to the source
> http://blogten.blogspot.com/2008/06/drove-to-reno-today.html
> http://blogten.blogspot.com/2008/06/update-on-sqrtrounded.html
>
>
>>>
>>> Andres.
>>>
>>> _______________________________________________
>>> Pharo-project mailing list
>>> [hidden email]
>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
>>>
>>
>
> _______________________________________________
> Pharo-project mailing list
> [hidden email]
> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

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