[MatrixView] Fix assert in Eigen

[florent-lamiraux]

In Debug mode, in method Eigen::internal::variable_if_dynamic<T, Value>::setValue, if Value is not Dynamic there is a check that the input argument is equal to the Value template parameter. This check failed in the tests compiled in debug mode.

This modification fixes the issue.

[florent-lamiraux]

I tried to add a unit test in test/matrix-view.cc but I have not been able to make a matrix view of a matrix and to iterate on the blocks. If you can start something, I will be happy to finish it.

[jmirabel]

Have you seen the documentation of MatrixBlockView? The view is built using MatrixBlocks.[lr]view. Then it should be something like

for (MatrixBlockView::block_iterator block (view); block.valid(); ++block)
{
  // Access the current block
  view._block(block); // Returns an Eigen::Block object.
  // For the current block
  block.ri() // row, input
  block.ci() // col, input
  block.ro() // row, output
  block.co() // col, output
  block.rs() // number of rows
  block.cs() // number of cols
}