A Unified Algorithm for Virtual Desktops Placement in Distributed Cloud Computing

Algorithm 2

Modified first fit decreasing algorithm (MFFD).

Input: : numbers of BCs

  : feasible DC set for BC and

  : cost matrix of each DC as illustrated in Figure 1

  : VMs set for BC

Output: solution encoding

(1) for    do

(2)  Sort DCs in according to their capacity. Bigger DC

   is selected with higher probability and denote the sorted

   sequence as

(3)  for    do

(4)   while () and (exists not be searched)  do

(5)    Find smallest-cost-PM cluster with the largest

     capacity. Suppose there are total PMs in this

     cluster

(6)    Sort these PMs in non-increase capacity (21) and (22)

     order as

(7)    for    do

(8)     Select the biggest non-assigned VM from

      and put it into until is full

(9)      ∖VMs assigned to )

(10)      if    then

(11)      break

(12)      end if

(13)    end for

(14)   end while

(15)   if    then

(16)     break

(17)   end if

(18)  end for

(19)  if () and (all is searched) then

(20)   There is overflow, return FAILURE

(21)  end if

(22) end for

(23) Encoding the solution as according to Section 4.1