[Coin-discuss] Bug Report in PackedVectorBase

[Leo Lopes]

Hi Laszlo,

    I think I started my msg incorrectly, by even bringing up whether or 
not compiler A or B was at fault. I apologize for that. The question you 
brought up about how to deal with ANY compiler's bugs is an important 
one. My 2c on that is to treat each situation individually. The argument 
for that approach is that these days, almost always all that is required 
are very simple changes. Furthermore, the result is often code 
improvement, and sometimes when you are lucky even design improvements. 
At least that has been my experience.

    For this particular issue, I agree with your solution. I think that 
the binaryOp methods as they are now don't belong in PackedVectorBase. 
My (strictly academic, I admit) simplest arguments for that are: a base 
class should not have any knowledge about a derived class; and a method 
should not be used in a file if it isn't defined in that file or in a 
file included from that file.

    BTW, Kipp Martin tells me that with the changes I sent you COIN 
compiles cleanly and works on MSVC 03.


Cheers,
Leo.

Laszlo Ladanyi wrote:

>Hi Leo,
>
>Actually, I believe that MSVC 2003 is at fault. The binaryOp methods are
>templated methods and the compiler has no business in compiling them until it
>knows the template arguments. What I think is that MSVC 2003 tries to be
>clever and precompile those parts of the method that do not depend on the
>template argument. But that's a problem with the compiler. Also, Sun's CC,
>IBM's xlC, HP's aCC compile the code without any problems...
>
>This raises the issue of how do we deal with bugs in Microsoft's compilers?
>(The question is valid regardless of whether MSVC 2003 is at fault now or
>not.) To get wide audience, we need them to compile our code. But that would
>be sort of letting the bully to win. (The bully's compiler is faster, but only
>because it cheats on the rules, but we can't do anything about it, so we
>conform...)
>
>In this particular case moving binatyOp into the PackedVector class is not the
>right solution either. If we did that we couldn't use ShallowPackedVectors in
>binaryOps.
>
>A possible solution would be to move binaryOp into CoinPackedVector.hpp as a
>templated function (not a method in PackedVector. This actually makes sense,
>after all, the does function return a PackedVector...
>
>What do people think? (On both questions.)
>
>--Laci
>
>On Sat, 4 Oct 2003, Leo Lopes wrote:
>
>  
>
>>Dear Laszlo,
>>
>>	I was having trouble compiling the basic COIN library under the newest 
>>VS .net (I know, I know), and I noticed you were the last to update 
>>CoinPackedVectorBase and CoinPackedVector. I'd like to point out a 
>>feature of that code that is causing a problem. It is on lines 164, 182, 
>>and 200, and the couple of lines following each case. MSVC 2003 
>>complains about this code even though gcc and the previous MSVC don't, 
>>and I think at least this time MSVC 2003 is right.
>>
>>	The problem is the following: when compiling PackedVectorBase, a 
>>compiler has no way of knowing that PackedVector has a 
>>setTestForDuplicateIndex method. It doesn't know, at this point, that 
>>PackedVector is a child of PackedVectorBase. My guess is that the code 
>>as it is now only works in gcc and the old MSVC because of the mechanism 
>>that gcc and MSVC use to implement templates.
>>
>>	I changed PackedVectorBase and PackedVector so that any references to 
>>PackedVector are removed from its parent, PackedVectorBase. This 
>>involved moving the binaryOp functions to PackedVector and changing some 
>>signatures. This allowed the Coin library ato compile cleanly under MSVC 
>>and gcc and Clp to compile cleanly under gcc. I haven't tried other 
>>libraries/compilers combinations yet.
>>
>>	The sources I am sending you are not changes of the absolute newest 
>>versions in the CVS. However the same holds true of those versions.
>>
>>Cheers,
>>Leo.
>>
>>Laszlo Ladanyi wrote:
>>    
>>
>>>I think I caught all memory problems. At least now valgrind is quiet. It
>>>wasn't too bad, various pointers got deleted multiple times. I think there are
>>>memory leaks left. I'll try to deal with them over the weekend or early next
>>>week.
>>>
>>>All the changes are committed. 
>>>
>>>Thanks for the bug report!
>>>--Laci
>>>
>>>
>>>_______________________________________________
>>>Coin-discuss mailing list
>>>Coin-discuss at www-124.ibm.com
>>>http://www-124.ibm.com/developerworks/oss/mailman/listinfo/coin-discuss
>>>      
>>>
>>-- 
>>=======================================================================
>>Leonardo B. Lopes                                   leo at sie.arizona.edu
>>Visiting Assistant Professor                              (520)626-1780
>>SIE - University of Arizona
>>
>>    
>>
>
>  
>

-- 
=======================================================================
Leonardo B. Lopes                                   leo at sie.arizona.edu 
Visiting Assistant Professor                              (520)626-1780
SIE - University of Arizona