Eigen3 replicate () for cwiseProduct matrix vector
I have the following code:
Eigen::MatrixXf aMatrix( 3, 5 );
aMatrix <<
1, 0, 1, 0, 1,
0, 1, 0, 1, 0,
1, 1, 1, 1, 1;
Eigen::VectorXf aVector( 5 );
aVector << 3, 4, 5, 6, 7;
cout << aMatrix.cwiseProduct( aVector.replicate( 1, aMatrix.rows() ).transpose() ) << endl;
which outputs:
3 0 5 0 7
0 4 0 6 0
3 4 5 6 7
Is there a more efficient way to achieve this than using a challenge replicate()
?
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2 answers
Solved (with: How can I apply bsxfun functionality on Eigen? )
They are equivalent:
aMatrix.cwiseProduct( aVector.replicate( 1, aMatrix.rows() ).transpose() )
aMatrix.array().rowwise() * aVector.array().transpose()
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I'm not sure if this is more efficient, but repeated multiplication on a diagonal matrix is another option.
aMatrix * aVector.asDiagonal();
#include <iostream>
#include <Eigen/Dense>
int main()
{
Eigen::MatrixXf aMatrix( 3, 5 );
aMatrix <<
1, 0, 1, 0, 1,
0, 1, 0, 1, 0,
1, 1, 1, 1, 1;
Eigen::VectorXf aVector( 5 );
aVector << 3, 4, 5, 6, 7;
std::cout << aMatrix * aVector.asDiagonal() << std::endl;
return 0;
}
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