Brief Announcement: Sorting on Skip Chains Ajoy K. Datta, Lawrence L. Larmore, and Stéphane Devismes
Skip Chain October, 11, 2011SSS'2011, Grenoble2 Left Right Major nodes Relay nodes
Skip Chain Sorting October, 11, 2011SSS'2011, Grenoble
Contribution Skip Chain Sorting Algorithm – Self-stabilizing – Silent – Locally shared memory model Unfair demon O(b) space, b = number of bits to encode a value O(md) rounds – m : number of major nodes – d : maximum number of relay between two major nodes – md = O(n) if the spacing between major processes is roughtly equal October, 11, 2011SSS'2011, Grenoble4
Overview Idea : distributed bubble sort October, 11, 2011SSS'2011, Grenoble5 Arbitrary Configurations Normal Configurations Legitimate Configurations Error Correction Sorting
Data Structure October, 11, 2011SSS'2011, Grenoble
Swap October, 11, 2011SSS'2011, Grenoble Synchronization between swaps : 4 colors
Colors A value moves to the left at the crest of wave 0 A value moves to the right at the crest of wave 1 Colors 2 and 3 to avoid ambiguïty and to synchronize Color E: error color October, 11, 2011SSS'2011, Grenoble8
Example October, 11, 2011SSS'2011, Grenoble9 X Yz Compare and swap V(y)V(x)
Example October, 11, 2011SSS'2011, Grenoble10 X Yz V(y)’V(x)’ 0, V(x)’1, V(y)’
Example October, 11, 2011SSS'2011, Grenoble11 X Yz Compare and swap V(y)’V(x)’ V(y)’ V(u) V(x)’
Example October, 11, 2011SSS'2011, Grenoble12 X Yz Compare and swap V(y)’V(x)’ V(x)’’ V(y)’ V(u)’ 2 1, V(x)’’
Example October, 11, 2011SSS'2011, Grenoble13 X Yz V(y)’V(x)’’ V(y)’ V(u)’
Example October, 11, 2011SSS'2011, Grenoble14 X Yz V(y)’V(x)’’ V(y)’ V(u)’ 2 3
Example October, 11, 2011SSS'2011, Grenoble15 X Yz V(y)’V(x)’’ V(y)’ V(u)’
Example October, 11, 2011SSS'2011, Grenoble16 X Yz V(y)’V(x)’’ V(y)’ V(z) V(u)’ Compare and swap
Example October, 11, 2011SSS'2011, Grenoble17 X Yz V(y)’V(x)’’ V(y)’’ V(z)’ V(u)’ 0, V(y)’’ 3
Example October, 11, 2011SSS'2011, Grenoble18 X Yz V(y)’’V(x)’’ V(y)’’ V(z)’ V(u)’
Example October, 11, 2011SSS'2011, Grenoble19 X Yz V(y)’’V(x)’’ V(y)’’ V(z)’ V(u)’
Error correction October, 11, 2011SSS'2011, Grenoble20
Silence October, 11, 2011SSS'2011, Grenoble Done
Perspective Can we enhance the round complexity to O(n) rounds ? Step complexity ? October, 11, 2011SSS'2011, Grenoble22
Thank you October, 11, 2011SSS'2011, Grenoble23
Min-Max Search Tree October, 11, 2011SSS'2011, Grenoble <= 3 3 min max