Hi,

I'm new to Eigen and template programming, hope you can help me out with this one:

the function is:

Code: Select all

step(VectorXf &input);

and I do:

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step(trainsample.row(i));

The compiler complains:
no matching function for call to ‘step(Eigen::Block<Eigen::Matrix<float, -0x00000000000000001, 1, 0, -0x00000000000000001, 1>, 1, 1, true>)’

Trainsample is a VectorXf, so in my understanding the i'th row of it should be a VectorXf of length 1.

I'm using the 3.0beta1 of Eigen.

Cheers,
Victor

Edit: I think I found the reason why this does not work: viewtopic.php?f=74&t=88577&p=161739&hilit=segment#p161739

The solution is to declare input as const

If you're OK with your block being passed as const and you're OK with the block expression being evaluated into a temporary, then yes you can do just a const matrix reference.

Otherwise, the issue is that a block isn't a Matrix, it's a MatrixBase<T>. This question has been answered several times already, see also
http://eigen.tuxfamily.org/dox-devel/To ... Types.html
(but this page is for Eigen 3. For eigen 2, you want MatrixBase, not DenseBase.).