Efficiently Transforming from Spherical Coordinates to Cartesian Coordinates using Eigen

I need to transform the coordinates from spherical to Cartesian space using the Eigen C++ Library. The following code serves the purpose.

 const int size = 1000;
    Eigen::Array<std::pair<float, float>, Eigen::Dynamic, 1> direction(size);
    for(int i=0; i<direction.size();i++)
    {
            direction(i).first = (i+10)%360; // some value for this example (denoting the azimuth angle)
            direction(i).second = (i+20)%360; // some value for this example (denoting the elevation angle)

     }

    SSPL::MatrixX<T1> transformedMatrix(3, direction.size());
    for(int i=0; i<transformedMatrix.cols(); i++)
    {
        const T1 azimuthAngle = direction(i).first*M_PI/180;    //converting to radians
        const T1 elevationAngle = direction(i).second*M_PI/180; //converting to radians

        transformedMatrix(0,i) = std::cos(azimuthAngle)*std::cos(elevationAngle);
        transformedMatrix(1,i) = std::sin(azimuthAngle)*std::cos(elevationAngle);
        transformedMatrix(2,i) = std::sin(elevationAngle);
    }

I would like to know a better implementation is possible to improve the speed. I know that Eigen has supporting functions for Geometrical transformations. But I am yet to see a clear example to implement the same. Is it also possible to vectorize the code to improve the performance?