| More docs on the ARB website. See also index of helppages. Last update on 27. Jun 2017 .

Main topics:

- ARB: a Short Introduction
- Glossary
- NTREE MODES (general info)

Related topics:

- Multifurcate tree

# LENGTH and MULTIFURC MODE

- OCCURRENCE
- DESCRIPTION
- Differences between LENGTH- and MULTIFURC-MODES
- NOTES
- EXAMPLES
- WARNINGS
- BUGS

## OCCURRENCE

### ARB_NT <button in the left column>

## DESCRIPTION

### Both modes described here allow you to increase or reduce the length of terminal and internal branches.

### Click on the eleventh resp. twelfth button in the left column of the 'ARB_NT' window to activate the 'LENGTH MODE' resp. 'MULTIFURC MODE'.

### Change branch length:

Click and drag a branch to change its length.
If you use the right mouse button, discrete values will be used for the length.

### Set branch length to zero:

Point to a branch with the mouse and hit the key '0' (zero).

## Differences between LENGTH- and MULTIFURC-MODES

### The LENGTH MODE simply changes the length of the targeted branch.

### The MULTIFURC-MODE changes the length of the targeted branch as well, but also distributes its length-change to its direct (non-zero-length) neighbour-branches. Distribution is based on the same algorithm as ´Multifurcate tree´.

## NOTES

### To multifurcate explicit single branches, you may as well focus the tree-display, move the mouse pointer to the bootstrap value of the branch to eliminate and then press '0' to actually eliminate the branch.

### Increasing the length of a branch in MULTIFURC-MODE may cause neighbour branches to become multifurcations. This is irreversible, i.e. reducing the length back to the original value will not "un-multifurcate" the affected branches.

### In both modes it is possible to set branchlengths to negative values if expert-mode is enabled.

## EXAMPLES

### None

## WARNINGS

### In MULTIFURC MODE you may not expect to undo all length distributions, by scaling the branchlength back to the original value it had before a previous scale operation!

## BUGS

### unknown