diff --git a/R/cluster_logfc.R b/R/cluster_logfc.R
index db38b52..84853ae 100644
--- a/R/cluster_logfc.R
+++ b/R/cluster_logfc.R
@@ -16,7 +16,8 @@ if (is.factor(cluster.ids)==F) {
   cluster.ids <- as.factor(cluster.ids)
 }
 
-if (!class(expr.mat)=="dgCMatrix") {
+if (!inherits(expr.mat, "dgCMatrix")) {
+#if (!class(expr.mat)=="dgCMatrix") {
 	expr.mat <- Matrix(expr.mat,sparse=TRUE)
 }
 
diff --git a/R/wmw_gsea.R b/R/wmw_gsea.R
index 0d7b513..2ca8f14 100644
--- a/R/wmw_gsea.R
+++ b/R/wmw_gsea.R
@@ -18,7 +18,8 @@ wmw_gsea <- function(expr.mat,cluster.cells,log.fc.cluster,gene.sets)
 
 {
 
-if (!class(expr.mat)=="matrix") {
+if (!inherits(expr.mat, "matrix")) {
+#if (!class(expr.mat)=="matrix") {
 	expr.mat <- as.matrix(expr.mat)
 }