diff --git a/lib/www/server/lib/comparisons/pca.js b/lib/www/server/lib/comparisons/pca.js
index f4303b0..a44de89 100644
--- a/lib/www/server/lib/comparisons/pca.js
+++ b/lib/www/server/lib/comparisons/pca.js
@@ -15,9 +15,12 @@ function computePCA(deviations) {
 	// Compute mean for centering (1 x 2 matrix)
 	const mean = math.mean(D, 0);
 
-	// Explicitly repeat mean to match D's shape (n x 2)
+	// Manually repeat-mean to match D's shape (n x 2)
 	const n = deviationMatrix.length;
-	const meanRepeated = math.repmat(mean, n, 1);
+	const meanArr = mean.toArray();
+	const meanRepeated = math.matrix(
+		Array(n).fill().map(() => [meanArr[0], meanArr[1]])
+	);
 
 	// Center the data
 	const centered = math.subtract(D, meanRepeated);