/** Test method for {@link GroupElement#select(int, int)}. */
@Test
public void testSelect() {
GroupElement B = ed25519.getB();
for (int i = 0; i < 32; i++) {
// 16^i 0 B
assertThat(
i + ",0", B.select(i, 0), is(equalTo(GroupElement.precomp(curve, ONE, ONE, ZERO))));
for (int j = 1; j < 8; j++) {
// 16^i r_i B
GroupElement t = B.select(i, j);
assertThat(i + "," + j, t, is(equalTo(B.precmp[i][j - 1])));
// -16^i r_i B
t = B.select(i, -j);
GroupElement neg =
GroupElement.precomp(
curve, B.precmp[i][j - 1].Y, B.precmp[i][j - 1].X, B.precmp[i][j - 1].Z.negate());
assertThat(i + "," + -j, t, is(equalTo(neg)));
}
}
}
