Structure optimization

# Element: structureoptimization

The element structureoptimization activates the optimization of atomic postions.

 Type: no content XPath: /input/structureoptimization

This element allows for specification of the following attributes: epsforce, resume, tau0atm

## Attribute: epsforce

Convergence tolerance for the forces during a structural optimization run.

 Type: no content Default: "5.0d-5" Use: optional XPath: /input/structureoptimization

## Attribute: resume

Resumption of a structural optimization run using the density in STATE.OUT, but with positions from input.xml.

 Type: boolean Default: "false" Use: optional XPath: /input/structureoptimization/@resume

## Attribute: tau0atm

Parameter determining the step size for structural optimization.

In each step $m$ of a structural optimization run, atom $\alpha$ is displaced according to

(1)
\begin{align} {\bf r}_{\alpha}^{m+1}={\bf r}_{\alpha}^m+\tau_{\alpha}^m \left({ \bf F}_{\alpha}^m+{ \bf F}_{\alpha}^{m-1}\right), \end{align}

i.e., the magnitude of the displacement in step $m$ is proportional to $\tau_{\alpha}^m$. For the initial step, $\tau_{\alpha}^0$ is set to tau0atm. If the forces of two subsequent steps have the same sign, $\tau_{\alpha}^m$ is increased by $\tau_{\alpha}^0$. Otherwise, $\tau_{\alpha}^m$ is reset to $\tau_{\alpha}^0$.

 Type: fortrandouble Default: "0.2d0" Use: optional XPath: /input/structureoptimization/@tau0atm

# Reused Elements

The following elements can occur more than once in the input file. There for they are listed separately.

# Data Types

The Input definition uses derived data types. These are described here.