Initializing matrices from row vectors

[Matthias Moulin]

It would be nice to construct matrix instances using a 1D std::initializer_list containing the row vectors as opposed to only 2D or nested std::initializer_lists containing the scalar elements.

[Klaus Iglberger]

Hi Matthias!

Thanks for the suggestion. If I get the idea correctly, an alternative feature would be to provide a view that combines several vectors into a matrix, which could be used for both initialization and assignment. Could you please provide a short code example for which context you have in mind? Thanks again,

Best regards,

Klaus!

[Matthias Moulin]

My use cases are mostly related to transformations.

E.g., given a normal vector n, compute a tangent vector t and bitangent vector b and finally construct a transformation matrix from the resulting coordinate frame:

const blaze::StaticVector< float, 3u, blaze::rowVector > n_world = ...; // Obtain the normal vector.
const blaze::StaticVector< float, 3u, blaze::rowVector > t_world = ...; // Compute the tangent vector.
const blaze::StaticVector< float, 3u, blaze::rowVector > b_world = ...; // Compute the bitangent vector.
const blaze::StaticMatrix< float, 3u, 3u, blaze::columnMajor > tangent_to_world = { t_world, b_world, n_world }; // Construct a 3x3 (rotation) transformation matrix.
// ... or even more flexible ...
const blaze::StaticMatrix< float, 4u, 4u, blaze::columnMajor > tangent_to_world = { t_world, b_world, n_world, { 0.0f, 0.0f, 0.0f, 1.0f } }; // Construct a 4x4 affine transformation matrix.

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It is possible to use a view as well, but that requires an initialization and does not allow const.