# SystemAssembler¶

class dolfin.cpp.fem.SystemAssembler

This class provides an assembler for systems of the form Ax = b. It differs from the default DOLFIN assembler in that it applies boundary conditions at the time of assembly, which preserves any symmetries in A.

Constructor.

Parameters: const Form > a (std::shared_ptr<) – const Form > L (std::shared_ptr<) – std::shared_ptr< const DirichletBC >> bcs (std::vector<) –
assemble()

Assemble system (A, b) for (negative) increment dx, where x = x0 - dx is solution to system a == -L subject to bcs. Suitable for use inside a (quasi-)Newton solver.

Parameters: & A (GenericMatrix) – & b (GenericVector) – GenericVector & x0 (const) – void
thisown

The membership flag