clusterJudge_z_score: calculates the 'cluster judge' z-score

In pasculescu/ClusterJudge: Judging Quality of Clustering Methods using Mutual Information

Description

calculates the 'cluster judge' z-score as defined in the reference The z-score is based on shuffling the clusters at random and calculating the total mutual information relative to the entity.attribute table. After the selecetd number of randomizations the mean MR and standard deviation SDR of the mutual information is used in the definition of the z.score = (MI- MIR)/SDR where MI is the mutual information of the original clustering. The higher the z.score the better the clustering. A box-and-wisker plot is generated that shows how far is the clustering versus random clustering based on the mutual information to the selected entitity.attribute

Usage

clusterJudge_z_score(clusters, entity.attribute, nmb.randomizations = 30, plot.saveRDS.file=NULL)

Arguments

clusters	a named vectors of integers (or a factor). The names (or the levels of the factor) must match some (as many as possible) of the rownames of the entity.attribute table.
entity.attribute	data frame or matrix with 2 columns The assumption is that first column represent some 'entities' like gene names or gene ids. And the second column represents ‘attributes' of entities (for example Gene Ontology ID ’GO:0007260' which is 'tyrosine phosphorylation of STAT protein') Usually this is a consolidated entity.attribute where the attributes with very low number of entities or with very low mutual information have been removed (see consolidate_entity_attribute and the definition of Uncertainty on attributes mutual information)
nmb.randomizations	number of randomization iterations
plot.saveRDS.file	if not NULL must be a string represented a file location where the plot will be saved as an RDS object. The plot can be then retrieved at any time using readRDS function.

Value

a data.frame with the number of randomization shuffles and the total mutual information calculated after each of the shuffles

Note

a dot is printed on the console after each randomization (shuffling) step

Author(s)

Adrian Pasculescu

References

Gibbons, F.D. and Roth F.P., (2002) Judging the Quality of Gene Expression-Based Clustering Methods Using Gene Annotation. Genome Research, vol. 12, pp1574-1581.

Examples

library('yeastExpData')
data(ccyclered)

clusters <- ccyclered$Cluster
###  convert from Gene names to the new standard of Saccharomyces Genome Database (SGD) gene ids
ccyclered$SGDID <- sub('^S','S00',ccyclered$SGDID)
names(clusters) <- ccyclered$SGDID

data(Yeast.GO.assocs)  #### obtain associations and consolidate them at uncertainty level 0.001
Yeast.GO.assocs.cons <- consolidate_entity_attribute(entity.attribute = Yeast.GO.assocs
                                                   , min.entities.per.attr =3
                                                   , mut.inf=mi.GO.Yeast
                                                   , U.limit = c(0.001)) 

#### calculate z.scores for the associations consolidated at 0.001 Uncertainty level
z.scores <- clusterJudge_z_score(clusters
                        , entity.attribute = Yeast.GO.assocs.cons[[0.001]]
                        , nmb.randomizations=30)

pasculescu/ClusterJudge documentation built on May 29, 2019, 4:52 p.m.