Dear list, 

I'm trying to fit a nested blockmodel to a (bipartite) network with ~10^6 edges. The algorithm minimize_nested_blockmodel_dl() doesn't terminate; it keeps on adding layers indefinitely until it runs out of memory / hits walltime, see below. What could be going on? 

Many thanks in advance, 

Peter

level 2 : replaced (94, 1) -> (94, 16) , dS: -15452.0134871 3

    l=3      B: 8 <- 16    shrinking 16 -> 11

    l=3      B: 8 <- 16    B=11  niter:     1  count:    1  breaks:  1  min_S: 1002.5742  max_S: 1002.5742  S: 1002.5742  ΔS:      0.00000  moves:     0 

    l=3      B: 8 <- 16    shrinking 11 -> 8

    l=3      B: 8 <- 16    B=8  niter:     1  count:    1  breaks:  1  min_S: 838.70438  max_S: 838.70438  S: 838.70438  ΔS:      0.00000  moves:     0 

    l=3  Current bracket: (2, 8, 16) (691.21840695494018, 838.70438205706921, 1340.6798309766764)

    l=3      B: 5 <- 8    shrinking 8 -> 5

    l=3      B: 5 <- 8    B=5  niter:     1  count:    0  breaks:  0  min_S: 752.39171  max_S: 753.34067  S: 752.39171  ΔS:    -0.948956  moves:     2 

    l=3      B: 5 <- 8    B=5  niter:     2  count:    0  breaks:  0  min_S: 751.86303  max_S: 753.34067  S: 751.86303  ΔS:    -0.528683  moves:     1 

    l=3      B: 5 <- 8    B=5  niter:     3  count:    1  breaks:  1  min_S: 751.86303  max_S: 753.34067  S: 751.86303  ΔS:      0.00000  moves:     0 

    l=3  Current bracket: (2, 5, 8) (691.21840695494018, 751.86302859686145, 838.70438205706921)

    l=3      B: 3 <- 5    shrinking 5 -> 3

    l=3      B: 3 <- 5    B=3  niter:     1  count:    0  breaks:  0  min_S: 720.12311  max_S: 720.62000  S: 720.12311  ΔS:    -0.496886  moves:     1 

    l=3      B: 3 <- 5    B=3  niter:     2  count:    1  breaks:  1  min_S: 720.12311  max_S: 720.62000  S: 720.12311  ΔS:      0.00000  moves:     0 

    l=3  Current bracket: (2, 3, 5) (691.21840695494018, 720.123114036723, 751.86302859686145)

    l=3  Current bracket: (2, 2, 3) (691.21840695494018, 691.21840695494018, 720.123114036723)

    l=3  Bisect at B = 2 with S = 691.2184069549402

    l=3  Best result: B = 2, S = 691.2184069549402

level 3 : replaced (16, 1) -> (16, 2) , dS: -628.252218219 4

    l=4  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=4  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=4  Bisect at B = 2 with S = 26.65330734662712

    l=4  Best result: B = 2, S = 26.65330734662712

level 4 : replaced (2, 1) -> (2, 2) , dS: -1.86264514923e-09 5

    l=5  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=5  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=5  Bisect at B = 2 with S = 26.65330734662712

    l=5  Best result: B = 2, S = 26.65330734662712

level 5 : replaced (2, 1) -> (2, 2) , dS: -1.86264514923e-09 6

    l=6  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=6  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=6  Bisect at B = 2 with S = 26.65330734662712

    l=6  Best result: B = 2, S = 26.65330734662712

level 6 : replaced (2, 1) -> (2, 2) , dS: -1.86264514923e-09 7

    l=7  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=7  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=7  Bisect at B = 2 with S = 26.65330734662712

    l=7  Best result: B = 2, S = 26.65330734662712

level 7 : replaced (2, 1) -> (2, 2) , dS: -1.86264514923e-09 8

    l=8  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=8  Current bracket: (2, 2, 2) (26.653307346627116, 26.653307346627116, 26.653307346627116)

    l=8  Bisect at B = 2 with S = 26.65330734662712

and l is increasing into the thousands if the left alone.