M.set(SSIZE-1, SSIZE-1, M.get(SSIZE-1, SSIZE-1) + 3.14159);
assertFalse(M.equals(D));
D.set(SSIZE-1, SSIZE-1, D.get(SSIZE-1, SSIZE-1) + 3.14159);
assertTrue(M.equals(D));
D = M.dense();
assertTrue(M.equals(D));
assertTrue(D.epsilonEquals(M, 0.1));
M.set(SSIZE-1, SSIZE-1, M.get(SSIZE-1, SSIZE-1) + 3.14159);
assertFalse(M.equals(D));
D.addAt(SSIZE-1, SSIZE-1, 3.14159); // also test addAt