message: Updated comments in PcaModel
diff: @@ -213,11 +213,12 @@ public:
  * vectors, but only the block that is relevant for the vertex \p vertex_id.
  *
  * Todo: Can we return a const & view that points into the original data?
  - * I think actually .block returns a const, and by not defining our function
  - * const, we might copy the data here actually?
  + * I think it's not that easy - if we return e.g. "const auto&", then the compiler complains about
  + * returning a reference to a temporary.
  + * This will probably help: https://eigen.tuxfamily.org/dox/classEigen_1_1Block.html
  *
  * @param[in] vertex_id A vertex index. Make sure it is valid.
  - * @return A 1x3? 3x1? matrix that points to the rows in the original basis.
  + * @return A 3 x num_principal_components matrix of the relevant rows of the original basis.
  */
  Eigen::MatrixXf get_rescaled_pca_basis_at_point(int vertex_id) const
  {
  @@ -247,7 +248,7 @@ public:
  * vectors, but only the block that is relevant for the vertex \p vertex_id.
  *
  * @param[in] vertex_id A vertex index. Make sure it is valid.
  - * @return A matrix that points to the rows in the original basis.
  + * @return A 3 x num_principal_components matrix of the relevant rows of the original basis.
  */
  Eigen::MatrixXf get_orthonormal_pca_basis_at_point(int vertex_id) const
  {
  