id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
8434	Sloan Ordering Gives Incorrect Results	Allen Barnett <allen@…>	Jeremiah Willcock	"I was trying to use Sloan ordering to reduce the bandwidth on a couple of my finite element meshes. It did not give very good results; the bandwidth after reordering was exactly equal to number of vertexes! So, I tried the example program here: http://www.boost.org/doc/libs/1_53_0/libs/graph/example/sloan_ordering.cpp
I expected the results given in the comments in the example file:
{{{
/*
  Sample Output
  #####################################
  ### First light of sloan-ordering ###
  #####################################

  original bandwidth: 8
  original profile: 42
  original max_wavefront: 7
  original aver_wavefront: 4.2
  original rms_wavefront: 4.58258

  Starting vertex: 0
  Pseudoperipheral vertex: 9
  Pseudoperipheral radius: 4

  Sloan ordering starting at: 0
    0 8 3 7 5 2 4 6 1 9
    bandwidth: 4
    profile: 28
    max_wavefront: 4
    aver_wavefront: 2.8
    rms_wavefront: 2.93258

  Sloan ordering without a start-vertex:
    8 0 3 7 5 2 4 6 1 9
    bandwidth: 4
    profile: 27
    max_wavefront: 4
    aver_wavefront: 2.7
    rms_wavefront: 2.84605

  ###############################
  ### sloan-ordering finished ###
  ###############################
*/
}}}
Instead I got:
{{{
#####################################
### First light of sloan-ordering ###
#####################################

original bandwidth: 8
original profile: 58
original max_wavefront: 7
original aver_wavefront: 4.2
original rms_wavefront: 4.58258

Starting vertex: 0
Pseudoperipheral vertex: 9
Pseudoperipheral radius: 4

Sloan ordering starting at: 0
  0 7 4 9 1 6 2 5 3 8 
  bandwidth: 8
  profile: 55
  max_wavefront: 6
  aver_wavefront: 3.6
  rms_wavefront: 3.94968

Sloan ordering without a start-vertex:
  8 5 4 9 1 7 6 2 0 3 
  bandwidth: 9
  profile: 66
  max_wavefront: 7
  aver_wavefront: 4.2
  rms_wavefront: 4.66905

###############################
### sloan-ordering finished ###
###############################
}}}
You can see that the current results are in line with what I was experiencing with my own meshes, namely, no reduction in bandwidth or profile.

Sloan ordering seems to have first appeared in boost 1.30.0. I tried that version too, and it gives essentially the same results as I see with 1.53. So, perhaps it's the comments in the example program that need to be updated and Sloan ordering is not appropriate for my meshes."	Bugs	closed	To Be Determined	graph	Boost 1.53.0	Problem	fixed