def test_lpol2index_index2lpol():
process = ArmaProcess([1, 0, 0, -0.8])
coefs, locs = lpol2index(process.arcoefs)
assert_almost_equal(coefs, [0.8])
assert_equal(locs, [2])
process = ArmaProcess([1, 0.1, 0.1, -0.8])
coefs, locs = lpol2index(process.arcoefs)
assert_almost_equal(coefs, [-0.1, -0.1, 0.8])
assert_equal(locs, [0, 1, 2])
ar = index2lpol(coefs, locs)
assert_equal(process.arcoefs, ar)
def test_lpol2index_index2lpol():
process = ArmaProcess([1, 0, 0, -0.8])
coefs, locs = lpol2index(process.arcoefs)
assert_almost_equal(coefs, [0.8])
assert_equal(locs, [2])
process = ArmaProcess([1, .1, .1, -0.8])
coefs, locs = lpol2index(process.arcoefs)
assert_almost_equal(coefs, [-.1, -.1, 0.8])
assert_equal(locs, [0, 1, 2])
ar = index2lpol(coefs, locs)
assert_equal(process.arcoefs, ar)