---
name: "inv_mass"
section: "3rheolef"
platform: "linux"
package: "librheolef-dev"
version: "6.1-2.1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/inv_mass"
---

# inv\_mass(3rheolef)

## NAME

**inv\_mass** -- invert of L2 scalar product

## SYNOPSIS

```
        form(const space& V, const space& V, "inv_mass");

```

## DESCRIPTION

Assembly the invert of the matrix associated to the L2 scalar product of the finite element space V:

```
                 /
                 |
        m(u,v) = | u v dx
                 |
                 / Omega

```

The V space may be either a **P0** or **P1d** discontinuous finite element spaces see form(2).

## EXAMPLE

The following piece of code build the invert of the mass matrix associated to the **P1d**  approximation:

```
        geo omega_h ("square");
        space Vh (omega_h , "P1d");
        form im (Vh, Vh, "inv_mass");

```

## SEE ALSO

form(2)