diff --git a/.github/workflows/pkgdown.yaml b/.github/workflows/pkgdown.yaml
index ed7650c..2bf01bf 100644
--- a/.github/workflows/pkgdown.yaml
+++ b/.github/workflows/pkgdown.yaml
@@ -26,6 +26,9 @@ jobs:
 
       - uses: r-lib/actions/setup-pandoc@v2
 
+      - name: Configure and setup Intel MKL environment
+        run: sudo apt install intel-mkl-full
+
       - uses: r-lib/actions/setup-r@v2
         with:
           use-public-rspm: true
diff --git a/DESCRIPTION b/DESCRIPTION
index 80de4b5..6f08ba2 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: diffusr
 Type: Package
 Title: Network Diffusion Algorithms
-Version: 0.2.2
+Version: 0.2.3
 Date: 2018-04-20
 Authors@R: person("Simon", "Dirmeier",
                   email = "simon.dirmeier@gmx.de",
diff --git a/R/is.dgCMatrix.R b/R/is.dgCMatrix.R
index 7ee5a0e..751b502 100644
--- a/R/is.dgCMatrix.R
+++ b/R/is.dgCMatrix.R
@@ -31,7 +31,7 @@ assert_dgCMatrix <- function(adj_matrix, non_negative = TRUE) {
   } else if (non_negative && any(adj_matrix@x < 0)) {
     stop(paste("Error: Assertion on 'adj_matrix' failed: Element",
                seq_along(adj_matrix@x)[adj_matrix@x < 0][1], "is not >= 0."))
-  } else if (colAnyNAs(adj_matrix)) {
+  } else if (sum(colAnyNAs(adj_matrix))) {
     stop("Error: NAs in the matrix.")
   }
 }