Matrix

> Hi,
> i use Pharo-1.1-11411 and got a few questions.
> i looked at the comments of Matrix:
>
> it talks about Array2D but this object does not exist?
>
> it says "Element-wise matrix arithmetic works", but this is not true:
> while + - * functions in this way: aNumber + aMatrix, "/" does not always function:
> aSmallInteger / aMatrix produces an error, because aMatrix is tested with isZero.
> a simple fix would be to change the first program line in SmallInteger>>/ from:
> aNumber isZero ifTrue: [^(ZeroDivide dividend: self) signal]. to:
> (aNumber isNumber and: [aNumber isZero]) ifTrue: [^(ZeroDivide dividend: self) signal].
> further aMatrix + aNumber and similar arithmetic dont work. but with the above fix it would work nicely with  simple implementations like this:
> Collection>>/
> / aNumber
> ^aNumber  adaptToCollection: self  andSend: #/
> and so forth.
>
> while testing these things with Fractions, i noticed this:
> printing {3/4} produces this output:{(3/4)}.
> printing {{0.75}} produces this output:#(#(0.75)).
> printing {{3/4}} produces this output:{((Array new: 1) at: 1 put: (3/4); yourself)}.
> i wonder what the last output wants to tell me? does it want to tell me, that the last thing uses up a lot more memory than the first two, and accessing it takes more time, so that i should use the second thing instead, or is it (more or less) just print output related?
> werner
>

> Hi,
> i use Pharo-1.1-11411 and got a few questions.
> i looked at the comments of Matrix:
>
> it talks about Array2D but this object does not exist?
>
> it says "Element-wise matrix arithmetic works", but this is not true:
> while + - * functions in this way: aNumber + aMatrix, "/" does not always
> function:
> aSmallInteger / aMatrix produces an error, because aMatrix is tested with
> isZero.
> a simple fix would be to change the first program line in SmallInteger>>/
> from:
> aNumber isZero ifTrue: [^(ZeroDivide dividend: self) signal]. to:
> (aNumber isNumber and: [aNumber isZero]) ifTrue: [^(ZeroDivide dividend:
> self) signal].
> further aMatrix + aNumber and similar arithmetic dont work. but with the
> above fix it would work nicely with  simple implementations like this:
> Collection>>/
> / aNumber
> ^aNumber  adaptToCollection: self  andSend: #/
> and so forth.
>
> while testing these things with Fractions, i noticed this:
> printing {3/4} produces this output:{(3/4)}.
> printing {{0.75}} produces this output:#(#(0.75)).
> printing {{3/4}} produces this output:{((Array new: 1) at: 1 put: (3/4);
> yourself)}.
> i wonder what the last output wants to tell me? does it want to tell me,
> that the last thing uses up a lot more memory than the first two, and
> accessing it takes more time, so that i should use the second thing instead,
> or is it (more or less) just print output related?
> werner
>
>

> Hi Hernán,
> i had a superficial look at DHBNumerical and it does indeed what i wanted to
> do, thanks again.
> i ran DHB-Numerical-Tests and it showed 5 errors.i added this method:
> DhbNevilleInterpolator>>initialize
> super initialize.
> leftErrors :=#().
> rightErrors :=#()
> and the tests showed only 1 error. i havent looked, what the code does, it
> was only an instinctive fix, hence use with caution. the last error is not
> fixable in this instinctive way, one would have to understand how
> DhbClusterFinder actually finds clusters, and i have not yet looked at the
> doku and dont have the time at the moment.
> werner
>
>

> Thanks Werner, I will check later with the VW image too but I've
> integrated your fix. I've splitted the tests to their own package. The
> repository is world writable so feel free to add future improvements.
>
> Hernán
>
> 2011/2/3 Werner Kassens <[hidden email]>:
>> Hi Hernán,
>> i had a superficial look at DHBNumerical and it does indeed what i wanted to
>> do, thanks again.
>> i ran DHB-Numerical-Tests and it showed 5 errors.i added this method:
>> DhbNevilleInterpolator>>initialize
>> super initialize.
>> leftErrors :=#().
>> rightErrors :=#()
>> and the tests showed only 1 error. i havent looked, what the code does, it
>> was only an instinctive fix, hence use with caution. the last error is not
>> fixable in this instinctive way, one would have to understand how
>> DhbClusterFinder actually finds clusters, and i have not yet looked at the
>> doku and dont have the time at the moment.
>> werner
>>
>>
>

> Could you add that didier agreed to release his code under MIT
> Tx
>
> Stef
>
> On Feb 3, 2011, at 4:43 PM, Hernán Morales Durand wrote:
>
>> Thanks Werner, I will check later with the VW image too but I've
>> integrated your fix. I've splitted the tests to their own package. The
>> repository is world writable so feel free to add future improvements.
>>
>> Hernán
>>
>> 2011/2/3 Werner Kassens <[hidden email]>:
>>> Hi Hernán,
>>> i had a superficial look at DHBNumerical and it does indeed what i wanted to
>>> do, thanks again.
>>> i ran DHB-Numerical-Tests and it showed 5 errors.i added this method:
>>> DhbNevilleInterpolator>>initialize
>>> super initialize.
>>> leftErrors :=#().
>>> rightErrors :=#()
>>> and the tests showed only 1 error. i havent looked, what the code does, it
>>> was only an instinctive fix, hence use with caution. the last error is not
>>> fixable in this instinctive way, one would have to understand how
>>> DhbClusterFinder actually finds clusters, and i have not yet looked at the
>>> doku and dont have the time at the moment.
>>> werner
>>>
>>>

> 2011/2/3 Stéphane Ducasse<[hidden email]>:
>> Could you add that didier agreed to release his code under MIT
>> Tx
>>
>> Stef
>>
>> On Feb 3, 2011, at 4:43 PM, Hernán Morales Durand wrote:
>>
>>> Thanks Werner, I will check later with the VW image too but I've
>>> integrated your fix. I've splitted the tests to their own package. The
>>> repository is world writable so feel free to add future improvements.
>>>
>>> Hernán
>>>
>>> 2011/2/3 Werner Kassens<[hidden email]>:
>>>> Hi Hernán,
>>>> i had a superficial look at DHBNumerical and it does indeed what i wanted to
>>>> do, thanks again.
>>>> i ran DHB-Numerical-Tests and it showed 5 errors.i added this method:
>>>> DhbNevilleInterpolator>>initialize
>>>> super initialize.
>>>> leftErrors :=#().
>>>> rightErrors :=#()
>>>> and the tests showed only 1 error. i havent looked, what the code does, it
>>>> was only an instinctive fix, hence use with caution. the last error is not
>>>> fixable in this instinctive way, one would have to understand how
>>>> DhbClusterFinder actually finds clusters, and i have not yet looked at the
>>>> doku and dont have the time at the moment.
>>>> werner
>>>>
>>>>