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

# lumped\_mass(3rheolef)

## NAME

**lumped\_mass** -- lumped L2 scalar product

## SYNOPSIS

```
        form(const space& V, const space& V, "lumped_mass");
        form(const space& M, const space& V, "lumped_mass");
        form (const space& V, const space& V, "lumped_mass", const domain& gamma);
        form_diag(const space& V, "mass");

```

## EXAMPLE

The use of lumped mass form write:

```
        form m(V, "lumped_mass");

```

or (see also mass(3)):

```
        form_diag md(V, "mass");

```

The lumped procedure sums all extra-diagonal terms on the diagonal: let us denote M the original mass matrix, then, the lumped mass matrix is the diagonal matrix defined by:

```
                    n
                   ----
                           M1(i,i) =  /    M(i,j)
                   ----
                    j=1

```

## SEE ALSO

mass(3)