Bin Selection
Bin sensitivity: is the gradient of BFCT
It reflects the responsiveness of the bin fraction to the bin motion of node T.
Example: If maximum slope of bin fraction is between k-1 and k, moving the tagged node from bin k-1 to k will shift the largest fraction of free nodes to their L bins. (alternatively, moving k to k-1 will result largest reduction in area)
Hence select (k-1)th bin.