[eigen] TriangularView::solve() interface

[Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx>]

Hello,

While rewriting part of the tutorial, I noticed that the new 
TriangularView::solve() function returns the solution vector, while the 
other solve functions pass the solution via one of the parameters. Compare

   x = A.triangularView<UpperTriangular>().solve(b);

with

   A.partialLu().solve(b, &x);

Was this done on purpose?

The docs on the eigen website [1] were magically updated, but some of the 
latex was not parsed correctly. Am I doing anything wrong? Everything 
works fine on my own computer.

[1] http://eigen.tuxfamily.org/dox-devel/TutorialAdvancedLinearAlgebra.html

Something to perhaps add to the to-do list: a routine to estimate the 
condition number of a matrix based on the LU decomposition.

Cheers,
Jitse