integrate_option2rheolef

Overview

This class is used to send options to the integrate function when building a form. It allows one to set the quadrature formulae that is used for numerical integration see quadrature_option(2) and two boolean flags.

Flags

ignore_sys_coord

This flag has effects only for axisymmetric coordinate systems. When set, it omits the r weight in the r dr dz measure during the numerical integration performed the integrate function. This feature is useful for computing the stream function in the axisymmetric case.

lump

This flag, when set, performs a mass lumping procedure on the matrix at the element level:

a(i,i) := sum(j) a(i,j)

The resulting matrix is diagonal. This feature is useful for computing a diagonal approximation of the mass matrix for the continuous P1 element.

invert

This flag, when set, performs a local inversion on the matrix at the element level:

a := inv(a)

This procedure is allowed only when the global matrix is block diagonal, e.g. for discontinuous or bubble approximations. This property is true when basis functions have a compact support inside exactly one element.

Default flag values

All flags are set to false by default.

Implementation

struct integrate_option : quadrature_option {
// allocators:
  integrate_option();
  integrate_option (const integrate_option& fopt);
  integrate_option (const quadrature_option& qopt);
  integrate_option& operator= (const integrate_option& fopt);
// data:
  bool ignore_sys_coord, lump, invert;
};