public static String realMatToString(RealMatrix r) { String res = "RealMatrix(" + r.getRowDimension() + "x" + r.getColumnDimension() + ") of type '" + r.getClass().getName() + "'\n"; for (int i = 0; i < r.getRowDimension(); i++) { res += Arrays.toString(r.getRow(i)) + "\n"; } return res; }