| Re: [eigen] Eigen 3.0-beta1 operator+= problem |
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Many thanks for this, I will try again with the development branch.
Gavin.
On 6 Sep 2010, at 11:36, Gael Guennebaud wrote:
> thank you for the self-contained test case. problem solved with
> respective unit tests.
>
> gael
>
> On Mon, Sep 6, 2010 at 12:42 AM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>> Problem confirmed with current development branch.
>>
>> gdb tells me it's picking up the operator+= defined at
>> Eigen/src/Core/CwiseBinaryOp.h:232:
>>
>> template<typename Derived>
>> template<typename OtherDerived>
>> EIGEN_STRONG_INLINE Derived &
>> MatrixBase<Derived>::operator+=(const MatrixBase<OtherDerived>& other)
>> {
>> SelfCwiseBinaryOp<ei_scalar_sum_op<Scalar>, Derived, OtherDerived>
>> tmp(derived());
>> tmp = other.derived();
>> return derived();
>> }
>>
>> So this is likely a bug in SelfCwiseBinaryOp. That's all I can do for today...
>>
>> Benoit
>>
>> 2010/9/5 Gavin Band <gavin.band@xxxxxxxxxxxxx>:
>>> Dear Eigen list,
>>>
>>> I decided to evaluate Eigen and (wanting to dive in at the deep end) downloaded Eigen 3.0 beta. However, I immediately ran into the problem exemplified by the code below, in which using operator+= seems to give a different answer than using operators + and = separately when the rhs is the result of ColPivHouseholderQR::solve(). (The problem did not occur with a plain MatrixXd on the right.) Is this behaviour a bug, or am I doing something wrong?
>>>
>>> Many thanks,
>>> Gavin Band.
>>>
>>> // ==== begin code ====
>>>
>>> #include <iostream>
>>> #include <Eigen/Dense>
>>>
>>> int main()
>>> {
>>> Eigen::VectorXd pt( 1 ), v1( 1 ), v2( 1 ) ;
>>> pt << 1 ;
>>> v1 << 1 ;
>>> v2 << 1 ;
>>>
>>> Eigen::MatrixXd M( 1, 1 ) ;
>>> M << 1.0 ;
>>>
>>> Eigen::ColPivHouseholderQR< Eigen::MatrixXd > decomposer( M ) ;
>>>
>>> v1 += decomposer.solve( pt ) ; // value is 1 ???
>>> v2 = v2 + decomposer.solve( pt ) ; // value is 2, ok.
>>>
>>> std::cerr << "QR = " << decomposer.matrixQR() << ", v1 = " << v1 << ", v2 = " << v2 << ".\n" ;
>>> }
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>