I need a few explanations about ldu addressing
 

I read some articles and posts of this forum about LDU addressing .
If I am right :
upperAddr() gives me the rows of the upper-triangle matrix and the columns of the lower-triangle matrix .
lowerAddr() gives me the rows of the lower-triangle matrix and the columns of the upper-triangle matrix .

Now, what I can't understand, what give me for example, ownerSortAddr(), ownerStartAddr(), losortAddr(),losortStartAddr() ?

I think that ownerStartAddr()[k] gives me the first element of the row of the upper-element which id is k . And that losortStartAddr()[k] gives the first element of the column of this element . Am I right ?

Thanks .