# R/DESP_Weighted_Graph.R In DESP: Estimation of Diagonal Elements of Sparse Precision-Matrices

#### Documented in DESP_Weighted_Graph

```# DESP/R/DESP_Weighted_Graph.R by A. S. Dalalyan and S. Balmand  Copyright (C) 2015-
#
#  This program is free software; you can redistribute it and/or modify
#  the Free Software Foundation.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  A copy of the GNU General Public License is available at
#

DESP_Weighted_Graph <-
function(B,n) {
# get a graph representation from the matrix B
# the resulting graph is a weighted undirected without loops
# the weights of the edges depend on squared partial correlations

D = dim(B);
p = D[2];               # p is the dimension

# compute off-diagonal squared partial correlations
SPC = DESP_SqPartCorr(B-diag(p),n);

# matrix of weights computation
W = exp(-SPC)*(SPC!=0);

# conversion to a sparse matrice stored in compressed sparse row format
W = as.matrix.csr(W);

# graph representation build from a sparse matrice
# graphNEL : This is a class of graphs that are represented in terms of nodes and an edge list. This is a suitable representation for a graph with a large number of nodes and relatively few edges.
G = sparseM2Graph(W, nodeNames=as.character(c(1:p)), edgemode="undirected")

return(G)
}
```

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DESP documentation built on May 29, 2017, 9:27 p.m.