tree b5238443254afef9a8b1456aa0f2adf3cd120ae6
parent 1b17145adf6aa0072db2989ad799e90313970ab3
author Sameer Agarwal <sameeragarwal@google.com> 1405632918 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1406869534 -0700

Enable Eigen as sparse linear algebra library.

SPARSE_NORMAL_CHOLESKY and SPARSE_SCHUR can now be used
with EIGEN_SPARSE as the backend.

The performance is not as good as CXSparse. This needs to be
investigated. Is it because the quality of AMD ordering that
we are computing is not as good as the one for CXSparse? This
could be because we are working with the scalar matrix instead
of the block matrix.

Also, the upper/lower triangular story is not completely clear.
Both of these issues will be benchmarked and tackled in the
near future.

Also included in this change is a bunch of cleanup to the
SparseNormalCholeskySolver and SparseSchurComplementSolver
classes around the use of the of defines used to conditionally
compile out parts of the code.

The system_test has been updated to test EIGEN_SPARSE also.

Change-Id: I46a57e9c4c97782696879e0b15cfc7a93fe5496a