Re: conjugate() and adjoint() bug example (Re: [eigen] Lazy evaluation and adjoint())

[Rasmus Larsen <rmlarsen@xxxxxxxxxx>]

Cool, thanks. Better safe than sorry :-)

On Thu, Sep 15, 2016 at 1:59 AM, Gael Guennebaud <gael.guennebaud@xxxxxxxxx> wrote:

of course! I did measure before pushing! 

gael

On Wed, Sep 14, 2016 at 8:51 PM, Rasmus Larsen <rmlarsen@xxxxxxxxxx> wrote:

Might be wise to measure rather than to hope... This is an extremely performance sensitive kernel.

On Wed, Sep 14, 2016 at 9:24 AM, Gael Guennebaud <gael..guennebaud@xxxxxxxxx> wrote:

Your example is missing:

namespace Eigen {

  template<> struct NumTraits<MyType>: NumTraits<TpComplex> {

  };

}

Then, it seems that my suggested fix, does solve your issue. Let's hope it does not degrade inlining...

gael

On Wed, Sep 14, 2016 at 4:16 PM, Peter <list@xxxxxxxxxxxxxxxxx> wrote:

Dear All,

I've composed a small example that shows highly non-expected behavior for conjugate and adjoint() for user defined Type,
see attached source file, which demonstrates that  conj() is not called in these cases for user defined types,
while it is called for std::complex.

//  typedef std::complex<double> MyUsedType;   ///< Use this for std complex type
typedef MyType MyUsedType;                   ///< Use this for user defined complex type


//typedef Eigen::Matrix< MyUsedType, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor> TpMatrix;
typedef Eigen::Matrix< MyUsedType, 2,2 > TpMatrix;


int main()
{
        MyUsedType z =  TpComplex(0, 1);
        MyUsedType u =  TpComplex(0.5, 0.5);
       
        TpMatrix  A(2,2), U(2,2);
       
        A << z, z,z,z;
        U << u, u, u, u;
       
        std::cout <<"# ------- Mark 1: ------- \n";
        MyType q = conj( z );
       
        std::cout <<"# ------- Mark 2: ------- \n";
        TpMatrix  R1 = U.adjoint() * A;
       
        std::cout <<"# ------- Mark 3: ------- \n";
        TpMatrix  R2 = U.adjoint();

        std::cout <<"# ------- Mark 4: ------- \n";
        A.adjointInPlace();

        std::cout <<"# ------- Mark 5: ------- \n";
        TpMatrix  R3 = A.conjugate();

        std::cout <<"# ------- Mark 6: ------- \n";

        std::cout << U(0,0) << " : " << R2(0,0) << std::endl;
        std::cout << A(0,0) << " : " << R3(0,0) << std::endl;
       
  return 0;
}

reports only one usage of conj() for MyType, for fixed size and dynamical matrices.
While the last 2 lines of output show, that for std::complex conjugation is performed.

Best regards,
Peter