Leaf Ordering Of Linkage Tree

Hi, I have a set N M-dimensional samples. I applied the linkage function in order to obtain the binary tree and I am trying to understand the difference between the leaf ordering performed by optimalleaforder and the one performed by the dendrogram function. I would expect that the optimalleaforder put near to one another leaf which are higly similar. Actually I could never test it due to the very long computational time. The ordering in dendrogram seems to do a similar thing but in much less time. I'm trying to figure out how it works but there are no references and I'm still working with the code.

Do you know what is the difference?

Thank you

[Daniele]

I run also the optimalleaforder function and actually the results are similar. But whereas the dendrogram ordering takes about 1 minute the optimalleaforder takes ours. I can't really understand why

[Daniele]

From the code I noticed that the optimalleaforder is based on the distance between the leah while the ordering in the dendrogram is based on only on the hierarchy of the nodes.