#       main topics:
UP      arb.hlp
UP      glossary.hlp
UP      mode.hlp

#       sub topics:
#SUB     subtopic.hlp

# format described in ../help.readme


TITLE           LENGTH and MULTIFURC MODE

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).

SECTION         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 LINK{multifurcate.hlp}.

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.

EXAMPLE         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
