How to convert between C++ ArrayFire and C++ Eigen matrices?

Question

I am new to Eigen and looking to learn ArrayFire for GPU acceleration. I would like to implement ArrayFire within my existing Eigen code rather than having to re-code all of my functions.

Is there a way to convert from an ArrayFire matrix to an Eigen matrix, and vice-versa?

Thanks!

Answer 1

Untested since I'm just looking at the ArrayFire documentation.

1. Copy Eigen matrix into a new AF array using this constructor:

Eigen::MatrixXf hostside = ...;
af::array deviceside(hostside.rows(), hostside.cols(), hostside.data());

It's important that a plain matrix or 2D array is used on Eigen's side (not an Eigen::Ref or other type of sub-matrix block) since neither the constructor nor any of the copy functions accept a column stride.

2. Copy host data into an existing device-side array

deviceside.write(hostside.data(), hostside.size() * sizeof(float));

3. Copy device-side data into an Eigen matrix

Eigen::MatrixXf hostside(deviceside.dims(0), deviceside.dims(1));
deviceside.host(hostside.data());