Merge branch 'SobolevDirectionalFilter'

CMakeLists.txt

IMPROVEMENTS.txt

common/data/element.cpp

common/data/element.h

common/functional.h

common/model/discretization.h

common/model/innerproduct/innerproduct.h

common/model/regularization/regularization.cpp

common/model/regularization/regularization.h

common/model/state.cpp

common/model/state.h

common/model/sweeper.cpp

common/model/sweeper.h

common/sensitivity/updater.cpp

common/sensitivity/updater.h

common/statefunctional.cpp

common/statefunctional.h

common/wave/correlation.h

directional.cpp

directional_field.cpp