[ADOL-C] result seems to differ for double and adouble

[Norman Goldstein]

That's a nice, clean, valgrind run.
Something next to consider trying is in your debugger,
to put a "change" watch on the variable location
that should be const.  You can set it to break
when the memory location changes value, and
then you can hopefully see who the culprit is.


On 08/11/2013 10:35 PM, Nozomu Tomita wrote:
> Dear all,
>
> Thank you for the quick reply.
> I tried valgrind, but (if my usage is correct) it found no error.
> (as I didn't use "new" or "[]" operator, I guess this is not from memory handling in this code)
>
> I could reduce my previous code...: http://pastebin.ca/2430872 ,
> and its output is this: http://pastebin.ca/2430873 .
>
> This code does a multiplication with a template class "wrap", for double and adouble.
> Line 15-18 of the output corresponds to line 25-34 of the source, with D == adouble.
> Here a and b changes after multiplication, in spite of its type "wrap<const adouble>"
> (consequently its member is of type "const adouble").
>
> In this output the results (A's) are not different for double and adouble,
> but it will differ if a or b is used in calculation.
>
> "make_pair(-A,-A)" at line 32 of the source may be important, because replacing it to
> e.g. "make_pair(A,-A)" or "make_pair(-A,A)" changes output.
>
> About valgrind, on Fedora on virtual machine (as I couldn't make valgrind work in Mac and Debian), with
> $ valgrind -v ./a.out
> outputted this: http://pastebin.ca/2430874
>
> I got the same result in previous two environments and on Fedora above.
>
> Thank you,
> Tomita
>
> On 2013/08/12, at 0:12, Norman Goldstein <normvcr at telus.net> wrote:
>
>> Perhaps running a memory checker, such as valgrind on linux, would be insightful?
>>
>>
>> On 08/11/2013 12:55 AM, Nozomu Tomita wrote:
>>> Dear all,
>>>
>>> I'm writing 3-dimensional geometrical calculation, such as how long a line penetrates a box,
>>> with templated class.
>>>
>>> The problem is that my templated function returns different results for double and adouble,
>>> and "const adouble" quantities seem to change in the middle of calculation.
>>>
>>> I'm sorry for the mess of source code, but I couldn't pick out the exact place that harms...
>>>
>>> My code http://pastebin.ca/2430586 is meant to do an identical calculation for both double and adouble,
>>> checking whether a line that is parallel to z-axis and on (1/2, 1/2, 0), penetrates
>>> a square (0,0,0)-(1,0,0)-(1,1,0)-(0,1,0).
>>>
>>> That returns correctly true for double, but false for adouble.
>>> Compiling this with -DDEBUG produces this output: http://pastebin.ca/2430588
>>>
>>> Line 55 - 67 of this output correspond to line 173 - 216 of source with template argument Real==adouble.
>>> The Odd thing is that although X and u (and its members) are declared as const,
>>> they change during calculation, from line 57 (u == vector3(0(a), 0(a), 1(a)))
>>> and line 59 (u == vector3(0(a), 0(a), 0(a))).
>>>
>>>
>>> I tested this result for ADOL-C 2.4.1 in two environments:
>>> * Debian 6.0.1,
>>>   with g++ (Debian 4.4.5-8) 4.4.5
>>> * MacOS X 10.8.4,
>>>   with g++ i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)
>>>
>>>
>>> Thank you!
>>>
>>> Tomita
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>>> ADOL-C mailing list
>>> ADOL-C at list.coin-or.org
>>> http://list.coin-or.org/mailman/listinfo/adol-c
>>>
>>
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