Re: [ublas] VS2012 inconsistent Debug/Release results with lu_substitute() 1.55 & 1.52

Subject: Re: [ublas] VS2012 inconsistent Debug/Release results with lu_substitute() 1.55 & 1.52
From: tidswell (tidswell_at_[hidden])
Date: 2014-10-25 20:54:01

Thank you Nasos.

The bug Nasos identified crept in when I tried to extract a suitable 
sample for posting.

But I think I still have a problem:
  * lu_factorize() is returning 0 (which if I understand API correctly 
means not singular)
  * if I reenable the type checks then the upper triangular type check 
in lu_substitute() fails.
     (see my inserted #error in code fragment below)

Is it reasonable for the solution not to be upper triangular when the 
matrix is not singular ?

thanks,
- JT

template<class M, class E>
     void lu_substitute (const M &m, matrix_expression<E> &e) {
         typedef const M const_matrix_type;
         typedef matrix<typename E::value_type> matrix_type;

#if BOOST_UBLAS_TYPE_CHECK
         matrix_type cm1 (e);
#endif

         inplace_solve (m, e, unit_lower_tag ());

#if BOOST_UBLAS_TYPE_CHECK
         BOOST_UBLAS_CHECK (detail::expression_type_check (prod 
(triangular_adaptor<const_matrix_type, unit_lower> (m), e), cm1), 
internal_logic ());
         matrix_type cm2 (e);
#endif

         inplace_solve (m, e, upper_tag ());

#if BOOST_UBLAS_TYPE_CHECK
#error "This is the check that fails in debug!"
         BOOST_UBLAS_CHECK (detail::expression_type_check (prod 
(triangular_adaptor<const_matrix_type, upper> (m), e), cm2), 
internal_logic ());
#endif
     }

On 21/10/14 02:01, Nasos Iliopoulos wrote:
> jT,
> try this:
> change line:
> std::copy( &(input_data[0][0]), &(input_data[matSize-1][matSize-1]), 
> data.begin() );
>
> to:
> std::copy( &(input_data[0][0]), &(input_data[matSize-1][matSize-1]) + 
> ptrdiff_t(1), data.begin() );
>
> (The last iterator should be one past the last element)
>
> You might get another response that was sent prior to this and has 
> some further valid points you may want to keep in mind.
>
> -Nasos
>
> On 10/20/2014 07:53 AM, tidswell wrote:
>>
>> Folx,
>> ublas is not my specialty, so apologies if Ive done something silly, 
>> but as I get different results with Debug & Release builds on 
>> identical code, I think there is a problem in ublas's interaction 
>> with Visual Studio 2012.
>> [There may also be problems in my code, but I think its simple enough 
>> that I expect consistent answers (I view consistently wrong as better 
>> than inconsistent). ]
>>
>> MS Windows 7
>> Visual Studio 2012
>> Boost 1.55 or 1.52 (I think also earlier, but I didnt go back that 
>> far to test)
>>
>> Simple usage of Fredrik Orderud's LU decompisition matrix inversion
>> http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?LU_Matrix_Inversion 
>>
>>
>> I've disabled _SCL_SECURE_NO_WARNINGS because its not standard C++.
>>
>> Ive disabled BOOST_UBLAS_TYPE_CHECK because I wanted to check with 
>> error control flow caused differences.
>>
>> Any guidance on why the results are inconsistent ?
>>
>> thanks,
>> - JT
>>
>>
>>
>> _______________________________________________
>> ublas mailing list
>> ublas_at_[hidden]
>> http://lists.boost.org/mailman/listinfo.cgi/ublas
>> Sent to:athanasios.iliopoulos.ctr.gr_at_[hidden]
>
>
>
> _______________________________________________
> ublas mailing list
> ublas_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/ublas
> Sent to:tidswell_at_[hidden]