> ah, i know.
>
> b is a column-vector. you can't multiply colwise by it.
>
> Either make it a row-vector or multiply rowwise by it.
>
> 2010/9/29 Carlos Becker <
carlosbecker@xxxxxxxxx>:
>> I already tried that, and still doesn't work. I get the following error
>> (sorry for the flooding)
>> test.cpp:20: error: no match for ‘operator*’ in
>> ‘((Eigen::DenseBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >*)(&((Eigen::MatrixBase<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> >*)(& a))->Eigen::MatrixBase<Derived>::array [with
>> Derived = Eigen::Matrix<float, -0x00000000000000001, -0x00000000000000001,
>> 0, -0x00000000000000001,
>> -0x00000000000000001>]()))->Eigen::DenseBase<Derived>::colwise [with Derived
>> = Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >]() *
>> ((Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> >*)(& b))->Eigen::MatrixBase<Derived>::array [with
>> Derived = Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1>]()’
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note: candidates are:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >
>> Eigen::operator*(const std::complex<float>&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> > > Eigen::operator*(const float&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > > Eigen::operator*(const std::complex<float>&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> > >
>> Eigen::operator*(const float&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >
>> Eigen::operator*(const std::complex<float>&, const
>> Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::Matrix<float, -0x00000000000000001, -0x00000000000000001, 0,
>> -0x00000000000000001, -0x00000000000000001> > Eigen::operator*(const float&,
>> const Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> > Eigen::operator*(const std::complex<float>&,
>> const Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::Matrix<float, -0x00000000000000001, 1, 0, -0x00000000000000001, 1> >
>> Eigen::operator*(const float&, const Eigen::MatrixBase<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> >&)
>> [2]+ Done gedit test.cpp
>> cjb@cjb-laptop:/tmp/eigen$ g++ test.cpp -I.
>> test.cpp: In function ‘int main()’:
>> test.cpp:20: error: no match for ‘operator*’ in
>> ‘((Eigen::DenseBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >*)(&((Eigen::MatrixBase<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> >*)(& a))->Eigen::MatrixBase<Derived>::array [with
>> Derived = Eigen::Matrix<float, -0x00000000000000001, -0x00000000000000001,
>> 0, -0x00000000000000001,
>> -0x00000000000000001>]()))->Eigen::DenseBase<Derived>::colwise [with Derived
>> = Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >]() *
>> ((Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> >*)(& b))->Eigen::MatrixBase<Derived>::array [with
>> Derived = Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1>]()’
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note: candidates are:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >
>> Eigen::operator*(const std::complex<float>&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> > > Eigen::operator*(const float&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > > Eigen::operator*(const std::complex<float>&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::ArrayWrapper<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> > >
>> Eigen::operator*(const float&, const
>> Eigen::ArrayBase<Eigen::ArrayWrapper<Eigen::Matrix<float,
>> -0x00000000000000001, -0x00000000000000001, 0, -0x00000000000000001,
>> -0x00000000000000001> > >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >
>> Eigen::operator*(const std::complex<float>&, const
>> Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::Matrix<float, -0x00000000000000001, -0x00000000000000001, 0,
>> -0x00000000000000001, -0x00000000000000001> > Eigen::operator*(const float&,
>> const Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001,
>> -0x00000000000000001, 0, -0x00000000000000001, -0x00000000000000001> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:95: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple2_op<float,
>> std::complex<float> >, Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> > Eigen::operator*(const std::complex<float>&,
>> const Eigen::MatrixBase<Eigen::Matrix<float, -0x00000000000000001, 1, 0,
>> -0x00000000000000001, 1> >&)
>> ./Eigen/src/Core/../plugins/CommonCwiseUnaryOps.h:91: note:
>> const Eigen::CwiseUnaryOp<Eigen::ei_scalar_multiple_op<float>,
>> Eigen::Matrix<float, -0x00000000000000001, 1, 0, -0x00000000000000001, 1> >
>> Eigen::operator*(const float&, const Eigen::MatrixBase<Eigen::Matrix<float,
>> -0x00000000000000001, 1, 0, -0x00000000000000001, 1> >&)
>>
>>
>> On Wed, Sep 29, 2010 at 7:49 PM, Benoit Jacob <
jacob.benoit.1@xxxxxxxxx>
>> wrote:
>>>
>>> Does a.array().colwise() * b.array() work ?
>>>
>>> We're a bit pedantic if we require putting array() here since the
>>> colwise() makes it clear what you want to do...
>>>
>>> Benoit
>>>
>>> 2010/9/29 Carlos Becker <
carlosbecker@xxxxxxxxx>:
>>> > Hi Benoit. No, it doesn't work and it makes sense, since it would be
>>> > like
>>> > multiplying a vector by a vector algebraically, which has no sense for a
>>> > Matrix type (has it?)
>>> > I wanted to do element-wise multiplication, and I thought that
>>> > .array().colwise() would cope with that. Just to clarify, I want to do:
>>> > if A = [1 2;
>>> > 3 4]
>>> > and B = [a;b] (matlab notation)
>>> > then I want to get something like:
>>> > result = [ 1*a, 2*a;
>>> > 3*b 4*b ]
>>> > Should I do this another way? I thought that .array().colwise() was
>>> > defined
>>> > to apply the element-wise operation for every column vector in A.
>>> > Thanks
>>> >
>>> > On Wed, Sep 29, 2010 at 7:41 PM, Benoit Jacob <
jacob.benoit.1@xxxxxxxxx>
>>> > wrote:
>>> >>
>>> >> 2010/9/29 Carlos Becker <
carlosbecker@xxxxxxxxx>:
>>> >> > Hi all, I was trying to code something like this:
>>> >> > #include <Eigen/Dense>
>>> >> > using namespace Eigen;
>>> >> > using namespace std;
>>> >> > int main()
>>> >> > {
>>> >> > MatrixXf a;
>>> >> > VectorXf b;
>>> >> > a.resize(2,4);
>>> >> > b.resize(2);
>>> >> > a << 1,2,
>>> >> > 3,4,
>>> >> > 5,6,
>>> >> > 7,8;
>>> >> > b << 1,2;
>>> >> > a = a.array().colwise() * b;
>>> >>
>>> >> Here you're multiplying an array by a matrix.
>>> >>
>>> >> Doesn't a.colwise() * b work?
>>> >>
>>> >> Benoit
>>> >>
>>> >> > return 0;
>>> >> > }
>>> >> > Should this compile correctly? I want to multiply every column in
>>> >> > matrix
>>> >> > a,
>>> >> > element-wise, with vector b, but I cannot make it work
>>> >> > I hope I am not forgetting about something important here.
>>> >> > Cheers,
>>> >> > Carlos
>>> >>
>>> >>
>>> >
>>> >
>>>
>>>
>>
>>
>