diff --git a/alra.R b/alra.R
index 5c432b9..6f2eb68 100644
--- a/alra.R
+++ b/alra.R
@@ -205,7 +205,7 @@ alra.low.memory <- function( A_norm, k=0,q=10, quantile.prob = 0.001, use.mkl =
     #     A_norm_rank15_cor <- result.completed[[3]] # The actual adjusted, completed matrix
 
     cat(sprintf("Read matrix with %d cells and %d genes\n", nrow(A_norm), ncol(A_norm)))
-    if (class(A_norm) != 'matrix') {
+    if(!("matrix" %in% class(A_norm))) {
         stop(sprintf("A_norm is of class %s, but it should be of class matrix. Did you forget to run as.matrix()?",class(A_norm)))
     }