@@ -39,6 +39,10 @@ make_comb_mat_from_matrix = function(x, mode, top_n_sets = Inf, min_set_size = -

 	set_size = set_size[l]

 	x = x[, l, drop = FALSE]

+

+	if(ncol(x) > 15) {

+		stop_wrap("Currently number of sets <= 15 is only supported.")

+	}

 	if(is.null(rownames(x))) {

 		x_has_rownames = FALSE

@@ -83,7 +87,7 @@ make_comb_mat_from_matrix = function(x, mode, top_n_sets = Inf, min_set_size = -

 	comb_mat = t(comb_mat)

 	nc = ncol(comb_mat)

-	comb_mat2 = matrix(nrow = nrow(comb_mat), ncol = nc*(nc-1)/2)

+	comb_mat2 = Matrix::Matrix(0, nrow = nrow(comb_mat), ncol = nc*(nc-1)/2, sparse = TRUE)

 	rownames(comb_mat2) = rownames(comb_mat)

 	if(mode == "intersect") {

 		if(nc > 1) {

@@ -171,6 +175,9 @@ make_comb_mat_from_list = function(lt, mode, value_fun = length, top_n_sets = In

 	min_set_size = -Inf, universal_set = NULL, complement_size = NULL) {

 	n = length(lt)

+	if(n > 15) {

+		stop_wrap("Currently number of sets <= 15 is only supported.")

+	}

     nm = names(lt)

     if(is.null(nm)) {

     	stop_wrap("The list must have names.")

@@ -216,7 +223,7 @@ make_comb_mat_from_list = function(lt, mode, value_fun = length, top_n_sets = In

     	complement_size = value_fun(complement_set)

     }

-    comb_mat = matrix(FALSE, nrow = n, ncol = sum(choose(n, 1:n)))

+    comb_mat = Matrix::Matrix(FALSE, nrow = n, ncol = sum(choose(n, 1:n)), s)

     rownames(comb_mat) = nm

     j = 1

     for(k in 1:n) {

@@ -442,9 +449,7 @@ make_comb_mat = function(..., mode = c("distinct", "intersect", "union"),

 			value_fun = length

 		}

 	}

-	if(length(lt) > 10) {

-		stop_wrap("Currently number of sets <= 10 is only supported.")

-	}

+	

 	m = make_comb_mat_from_list(lt, value_fun, mode = mode, top_n_sets = top_n_sets, min_set_size = min_set_size, 

 		universal_set = universal_set, complement_size = complement_size)

 	if(remove_empty_comb_set) {

@@ -541,6 +546,7 @@ comb_size = function(m, degree = NULL) {

 #

 # == param

 # -m A combination matrix returned by `make_comb_mat`.

+# -readable Whether the combination represents as e.g. "A&B&C".

 #

 # == details

 # The name of the combination sets are formatted as a string

@@ -559,13 +565,25 @@ comb_size = function(m, degree = NULL) {

 #           c = sample(letters, 20))

 # m = make_comb_mat(lt)

 # comb_name(m)

-comb_name = function(m) {

+# comb_name(m, readable = TRUE)

+comb_name = function(m, readable = FALSE) {

 	set_on_rows = attr(m, "set_on_rows")

 	if(set_on_rows) {

-		apply(m, 2, paste, collapse = "")

+		nm = apply(m, 2, paste, collapse = "")

 	} else {

-		apply(m, 1, paste, collapse = "")

+		nm = apply(m, 1, paste, collapse = "")

 	}

+

+	if(readable) {

+		sn = set_name(m)

+		nm = sapply(strsplit(nm, ""), function(x) {

+			l = as.logical(as.numeric(x))

+			paste(sn[l], collapse = "&")

+		}

+		nm = unname(nm)

+	}

+

+	return(nm)

 }

 # == title