subreddit algebra

subrealg.r

load("z_score_matrix.RData")
nom <- colnames(z_score_matrix)
nom <- do.call(rbind, strsplit(nom, split="\\|"))
colnames(z_score_matrix) <- nom[,1]
R <- cor(z_score_matrix, use="pair")^2



findrelsubreddit <- function(cursubs,curops,numret=20, mat=R) {
    curvec = 0
    for(i in 1:length(cursubs)) {
	    curvec = ifelse(curops[i]=="+",
	    	list(curvec + mat[which(rownames(mat)==cursubs[i]),]),
	    	list(curvec - mat[which(rownames(mat)==cursubs[i]),]))[[1]]
    }
    curclosesubs = cosine(x=curvec,y=R)
    curclosesubso = order(curclosesubs,decreasing=TRUE)
    curclosesubsorder = curclosesubs[curclosesubso]
    curclosesubsorderc = curclosesubsorder[-which(tolower(names(curclosesubsorder))%in%cursubs)]
	return(tail(curclosesubsorderc,numret))
}

findrelsubreddit("Age of smoking initiation ", "+")