assignEdgeWeights {NetPathMiner} | R Documentation

## Assigning weights to network edges

### Description

This function computes edge weights based on a gene expression profile.

### Usage

    assignEdgeWeights(microarray, graph, use.attr, y, weight.method = "cor",
      complex.method = "max", missing.method = "median",
      same.gene.penalty = "median", bootstrap = 100, verbose = TRUE)

### Arguments

`microarray` | Microarray should be a Dataframe or a matrix, with genes as rownames, and samples as columns.
`graph` | An annotated igraph object.
`use.attr` | An attribute name to map `microarray` rows (genes) to graph vertices. The attribute must be annotated in `graph`, and the values correspond to `rownames` of `microarray`. You can check the coverage and if there are complex vertices using `getAttrStatus`. You can eliminate complexes using `expandComplexes`.
`y` | Sample labels, given as a factor or a character vector. This must be the same size as the columns of `microarray`
`weight.method` | A function, or a string indicating the name of the function to be used to compute the edge weights. The function is provided with 2 numerical verctors (2 rows from `microarray`), and it should return a single numerical value (or `NA`). The default computes Pearson's correlation.
`complex.method` | A function, or a string indicating the name of the function to be used in weighting edges connecting complexes. If a vertex has >1 attribute value, all possible pairwise weights are first computed, and given to `complex.method`. The default function is `max`.
`missing.method` | A function, or a string indicating the name of the function to be used in weighting edges when one of the vertices lack expression data. The function is passed all edge weights on the graph. Default is `median`.
`same.gene.penalty` | A numerical value to be assigned when 2 adjacent vertices have the same attribute value, since correlation and similarity measure will give perfect scores. Alternatively, `same.gene.penalty` can be a function, computing the penalty from all edge weights on the graph (excluding same-gene and missing values). The default is to take the `median`
`bootstrap` | An integer `n`, where the `weight.method` is perfomed on `n` permutations of the gene profiles, and taking the median value. Set it to `NA` to disable bootstrapping.
`verbose` | Print the progress of the function.

### Value

The input graph with `edge.weight` as an edge attribute. The attribute can be a list of weights if `y` labels were provided.

### Author(s)

Ahmed Mohamed

### Examples

    	## Convert a metabolic network to a reaction network.
     data(ex_sbml) # bipartite metabolic network of Carbohydrate metabolism.
     rgraph <- makeReactionNetwork(ex_sbml, simplify=TRUE)

    	## Assign edge weights based on Affymetrix attributes and microarray dataset.
     # Calculate Pearson's correlation.
    	data(ex_microarray)	# Part of ALL dataset.
    	rgraph <- assignEdgeWeights(microarray = ex_microarray, graph = rgraph,
    		weight.method = "cor", use.attr="miriam.uniprot",
    		y=factor(colnames(ex_microarray)), bootstrap = FALSE)

     # Using Spearman correlation, assigning missing edges to -1
     ## Not run:
       assignEdgeWeights(microarray, graph, use.attr="miriam.affy.probeset",
           y=factor(colnames(microarray)),
           weight.method = function(x1,x2) cor(x1,x2, method="spearman"),
           missing.method = -1)

    ## End(Not run)

[Package NetPathMiner version 1.28.0 Index]