We present the performances of GREMLINS on a simulated multipartite network. GREMLINS includes a function rMBM to simulate multipartite networks. Mathematical details can be found in @multipartite.

## Simulation of a complex multipartite newtwork.

We use the function rMBM provided in the package to simulate a multipartite network involving $$2$$ functional groups (namely A and B) of respective sizes $n_A = 60, \quad, n_B = 50.$

A and B are divided respectively into $$3$$ and $$2$$ blocks. The sizes of the blocks are generated randomly. For reproductibility, we fix the random seed to an arbitrarily chosen value.

namesFG <- c('A','B')
v_NQ <-  c(60,50) #size of each FG
list_pi = list(c(0.16 ,0.40 ,0.44),c(0.3,0.7)) #proportion of each block in each  FG
list_pi[]
#>  0.16 0.40 0.44


We assume that we observe $$3$$ interactions matrices

- A-B : continuous weighted interactions
- B-B : binary interactions
- A-A : counting directed interactions

E  <-  rbind(c(1,2),c(2,2),c(1,1))
v_distrib <- c('ZIgaussian','bernoulli','poisson')


Note that the distributions may be Bernoulli, Poisson, Gaussian or Laplace (with null mean). For the Gaussian distribution, a mean and a variance must be given. We generate randomly the emission parameters $$\theta$$.

list_theta <- list()
list_theta[] <- list()
list_theta[]$mean <- matrix(c(6.1, 8.9, 6.6, 9.8, 2.6, 1.0), 3, 2) list_theta[]$var  <-  matrix(c(1.6, 1.6, 1.8, 1.7 ,2.3, 1.5),3, 2)
list_theta[]$p0 <- matrix(c(0.4, 0.1, 0.6, 0.5 , 0.2, 0),3, 2) list_theta[] <- matrix(c(0.7,1.0, 0.4, 0.6),2, 2) m3 <- matrix(c(2.5, 2.6 ,2.2 ,2.2, 2.7 ,3.0 ,3.6, 3.5, 3.3),3,3 ) list_theta[] <- (m3 + t(m3))/2# for symetrisation  We are now ready to simulate the data library(GREMLINS) dataSim <- rMBM(v_NQ,E , typeInter, v_distrib, list_pi, list_theta, namesFG = namesFG, seed = 4,keepClassif = TRUE) list_Net <- dataSim$list_Net
length(list_Net)
#>  3
names(list_Net[])
#>  "mat"       "typeInter" "rowFG"     "colFG"
list_Net[]$typeInter #>  "inc" list_Net[]$rowFG
#>  "A"
list_Net[]$colFG #>  "B"  ## Inference with model selection The model selection and the estimation are performed with the function multipartiteBM. res_MBMsimu <- multipartiteBM(list_Net, v_distrib = v_distrib, namesFG = c('A','B'), v_Kinit = c(2,2), nbCores = 2, initBM = FALSE, keep = FALSE) #>  "------------Nb of entities in each functional group--------------" #> A B #> 60 50 #>  "------------Probability distributions on each network--------------" #>  "ZIgaussian" "bernoulli" "poisson" #>  "-------------------------------------------------------------------" #>  " ------ Searching the numbers of blocks starting from [ 2 2 ] blocks" #>  "ICL : -7085.81 . Nb of blocks: [ 2 2 ]" #>  "ICL : -5901.15 . Nb of blocks: [ 3 2 ]" #>  "Best model------ ICL : -5901.15 . Nb of clusters: [ 3 2 ] for [ A , B ] respectively"  We can now get the estimated parameters. res_MBMsimu$fittedModel[]$paramEstim$list_theta$AB$mean
#>          [,1]     [,2]
#> [1,] 1.004152 6.572955
#> [2,] 2.582062 8.881842
#> [3,] 9.994673 6.139221


extractClustersMBM produces the clusters in each functional group.

Cl <- extractClustersMBM(res_MBMsimu)


## Inference without model selection

One may also want to estimate the parameters for given numbers of clusters. The function multipartiteBMFixedModel is designed for this task.

res_MBMsimu_fixed <- multipartiteBMFixedModel(list_Net, v_distrib = v_distrib, nbCores = 2,namesFG = namesFG, v_K = c(3,2))
#>  "====================== First Forward Step =================="
#>  "====================== First Backward Step =================="
#>  "====================== Last Forward Step =================="
#>  "====================== Last Backward Step =================="
res_MBMsimu_fixed$fittedModel[]$paramEstim$v_K #>  3 2 extractClustersMBM(res_MBMsimu_fixed)$A
#> []
#>    1  4  5 10 11 13 15 16 17 23 24 25 27 29 32 33 34 35 39 40 42 48 51 56 57
#>  58 59 60
#>
#> []
#>    2  6  7  8 12 14 19 22 26 31 36 37 38 41 43 44 46 47 49 50 52
#>
#> []
#>    3  9 18 20 21 28 30 45 53 54 55


## Missing data

GREMLINS is also able to handle missing data. In the following experiment, we artificially set missing data in the previously simulated matrices.

############# NA data at random in any matrix
epsilon =  10/100
list_Net_NA <- list_Net
for (m in 1:nrow(E)){
U <-  sample(c(1,0),v_NQ[E[m,1]]*v_NQ[E[m,2]],replace=TRUE,prob  = c(epsilon, 1-epsilon))
matNA <- matrix(U,v_NQ[E[m,1]],v_NQ[E[m,2]])
list_Net_NA[[m]]$mat[matNA== 1] = NA if (list_Net_NA[[m]]$typeInter == 'adj') {
M <- list_Net_NA[[m]]$mat diag(M) <- NA M[lower.tri(M)] = t(M)[lower.tri(M)] list_Net_NA[[m]]$mat <- M
}
}

res_MBMsimuNA <- multipartiteBM(list_Net_NA,
v_distrib = v_distrib,
namesFG = c('A','B'),
v_Kinit = c(2,2),
nbCores = 2,
keep = FALSE)
#>  "------------Nb of entities in each functional group--------------"
#>  A  B
#> 60 50
#>  "------------Probability distributions on each network--------------"
#>  "ZIgaussian" "bernoulli"  "poisson"
#>  "-------------------------------------------------------------------"
#>  " ------ Searching the numbers of blocks starting from [ 2 2 ] blocks"
#>  "ICL : -6521.28 . Nb of blocks: [ 2 2 ]"
#>  "ICL : -5446.97 . Nb of blocks: [ 3 2 ]"
#>  " ------ Searching the numbers of blocks starting from [ 3 2 ] blocks"
#>  "ICL : -5446.97 . Nb of blocks: [ 3 2 ]"
#>  " ------ Searching the numbers of blocks starting from [ 1 2 ] blocks"
#>  "ICL : -6977.56 . Nb of blocks: [ 1 2 ]"
#>  "ICL : -6521.28 . Nb of blocks: [ 2 2 ]"
#>  "Best model------ ICL : -5446.97 . Nb of clusters: [ 3 2 ] for [ A , B ] respectively"


We then have a function to predict the missing edges (probability if binary or intensity if weighted)

pred <- predictMBM(res_MBMsimuNA)