---
name: "integrate_option"
section: "2rheolef"
platform: "linux"
package: "librheolef-dev"
version: "7.0-2+b1"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/integrate_option"
---

# integrate\_option(2rheolef)

send options to the integrate function

## NAME

**integrate\_option** - send options to the integrate function

## DESCRIPTION

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;
};

```

## SEE ALSO

quadrature\_option(2)

## COPYRIGHT

Copyright (C) 2000-2018 Pierre Saramito \<Pierre.Saramito@imag.fr\> GPLv3+: GNU GPL version 3 or later \<http://gnu.org/licenses/gpl.html\>. This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.