Skip to main content
Regular ultra-sparse graphs and related non-binary LDPC codes
This page collects some good ultra-sparse graphs that were obtained with a randomized Progressive Edge Growth (PEG) algorithm [1]. By ultra-sparse graph, we mean a bipartite graph with two constant connection degrees (dv,dc), and with dv=2. When the obtained graph has minimum size (smallest number of nodes), we indicate that the size is minimum*.
These particular graphs can have multiple possible applications, including building good non-binary LDPC codes in high order fields [2,3]. The graphs are stored in the MacKay A-list format (http://www.inference.phy.cam.ac.uk/mackay/CodesFiles.html).


[1] A. Venkiah, D. Declercq and C. Poulliat, "Design of Cages with a Randomized Progressive Edge-Growth Algorithm", in IEEE Commun. Letters, vol. 12(4), pp. 1-3, April 2008.
[2] X.-Y. Hu, E. Eleftheriou, D.-M. Arnold, "Regular and Irregular Progressive Edge-Growth Tanner Graphs", IEEE Trans. Info. Theo., 51(1), pp. 386-398, January 2005.
[3] C. Poulliat, M. Fossorier and D. Declercq, "Design of regular (2,dc)-LDPC codes over GF(q) using their binary images", accepted in IEEE Trans. Commun., 2007.



Graphs with (dv=2,dc=3)
[girth=6,N=6]  graph with (dv=2,dc=3,girth=6) and minimum* size N=6 
[girth=8,N=9]  graph with (dv=2,dc=3,girth=8) and minimum* size N=9 
[girth=10,N=15]  graph with (dv=2,dc=3,girth=10) and minimum* size N=15 
[girth=12,N=21]  graph with (dv=2,dc=3,girth=12) and minimum* size N=21 
[girth=14,N=36]  graph with (dv=2,dc=3,girth=14) and minimum* size N=36 
[girth=16,N=45]  graph with (dv=2,dc=3,girth=16) and minimum* size N=45 
[girth=18,N=114]  graph with (dv=2,dc=3,girth=18) and size N=114 
[girth=20,N=201]  graph with (dv=2,dc=3,girth=20) and size N=201 
[girth=22,N=447]  graph with (dv=2,dc=3,girth=22) and size N=447 
[girth=24,N=726]  graph with (dv=2,dc=3,girth=24) and size N=726 
[girth=26,N=1602]  graph with (dv=2,dc=3,girth=26) and size N=1602 


Graphs with (dv=2,dc=4)
[girth=6,N=10]  graph with (dv=2,dc=4,girth=6) and minimum* size N=10 
[girth=8,N=16]  graph with (dv=2,dc=4,girth=8) and minimum* size N=16 
[girth=10,N=38]  graph with (dv=2,dc=4,girth=10) and minimum* size N=38 
[girth=12,N=52]  graph with (dv=2,dc=4,girth=12) and minimum* size N=52 
[girth=14,N=260]  graph with (dv=2,dc=4,girth=14) and size N=260 
[girth=16,N=160]  graph with (dv=2,dc=4,girth=16) and minimum* size N=160 


Graphs with (dv=2,dc=5)
[girth=6,N=15]  graph with (dv=2,dc=5,girth=6) and minimum* size N=15 
[girth=8,N=25]  graph with (dv=2,dc=5,girth=8) and minimum* size N=25 
[girth=10,N=90]  graph with (dv=2,dc=5,girth=10) and size N=90 
[girth=12,N=105]  graph with (dv=2,dc=5,girth=12) and minimum* size N=105 


Graphs with (dv=2,dc=6)
[girth=6,N=21]  graph with (dv=2,dc=6,girth=6) and minimum* size N=21 
[girth=8,N=36]  graph with (dv=2,dc=6,girth=8) and minimum* size N=36 
[girth=10,N=189]  graph with (dv=2,dc=6,girth=10) and size N=189 
[girth=12,N=186]  graph with (dv=2,dc=6,girth=12) and minimum* size N=186 


Graphs with (dv=2,dc=7)
[girth=6,N=28]  graph with (dv=2,dc=7,girth=6) and minimum* size N=28 
[girth=8,N=49]  graph with (dv=2,dc=7,girth=8) and minimum* size N=49 
[girth=10,N=385]  graph with (dv=2,dc=7,girth=10) and size N=385 
[girth=12,N=840]  graph with (dv=2,dc=7,girth=12) and size N=840 


Graphs with (dv=2,dc=8)
[girth=6,N=36]  graph with (dv=2,dc=8,girth=6) and minimum* size N=36 
[girth=8,N=64]  graph with (dv=2,dc=8,girth=8) and minimum* size N=64 
[girth=10,N=680]  graph with (dv=2,dc=8,girth=10) and size N=680 


Graphs with (dv=2,dc=9)
[girth=6,N=45]  graph with (dv=2,dc=9,girth=6) and minimum* size N=45 
[girth=8,N=81]  graph with (dv=2,dc=9,girth=8) and minimum* size N=81 


Graphs with (dv=2,dc=10)
[girth=6,N=55]  graph with (dv=2,dc=10,girth=6) and minimum* size N=55 
[girth=8,N=100]  graph with (dv=2,dc=10,girth=8) and minimum* size N=100 


Graphs with (dv=2,dc=20)
[girth=6,N=210]  graph with (dv=2,dc=20,girth=6) and minimum* size N=210 
[girth=8,N=400]  graph with (dv=2,dc=20,girth=8) and minimum* size N=400 


Graphs with (dv=2,dc=30)
[girth=6,N=465]  graph with (dv=2,dc=30,girth=6) and minimum* size N=465 
[girth=8,N=900]  graph with (dv=2,dc=30,girth=8) and minimum* size N=900 


Graphs with (dv=2,dc=40)
[girth=6,N=820]  graph with (dv=2,dc=40,girth=6) and minimum* size N=820 
[girth=8,N=1600]  graph with (dv=2,dc=40,girth=8) and minimum* size N=1600 


Graphs with (dv=2,dc=50)
[girth=6,N=1275]  graph with (dv=2,dc=50,girth=6) and minimum* size N=1275 
[girth=8,N=2500]  graph with (dv=2,dc=50,girth=8) and minimum* size N=2500