second derivatives in 1D, 2D, and 3D.
2D-in-2D, and 1D-in-1D cases.
Allocating space for inverse map second derivatives in initialization routines.
…notation in comments to make formulation more clear.
…n used in systems_of_equations_ex7. Also, small change to ex7 (use default_quadrature_order).
Revert "A || A == A" This reverts commit e6275d7.
…s instead of PK2.