def check_qr(self, a):
# This test expects the argument `a` to be an ndarray or
# a subclass of an ndarray of inexact type.
a_type = type(a)
a_dtype = a.dtype
m, n = a.shape
k = min(m, n)
# mode == 'complete'
q, r = linalg.qr(a, mode='complete')
assert_(q.dtype == a_dtype)
assert_(r.dtype == a_dtype)
assert_(isinstance(q, a_type))
assert_(isinstance(r, a_type))
assert_(q.shape == (m, m))
assert_(r.shape == (m, n))
assert_almost_equal(dot(q, r), a)
assert_almost_equal(dot(q.T.conj(), q), np.eye(m))
assert_almost_equal(np.triu(r), r)
# mode == 'reduced'
q1, r1 = linalg.qr(a, mode='reduced')
assert_(q1.dtype == a_dtype)
assert_(r1.dtype == a_dtype)
assert_(isinstance(q1, a_type))
assert_(isinstance(r1, a_type))
assert_(q1.shape == (m, k))
assert_(r1.shape == (k, n))
assert_almost_equal(dot(q1, r1), a)
assert_almost_equal(dot(q1.T.conj(), q1), np.eye(k))
assert_almost_equal(np.triu(r1), r1)
# mode == 'r'
r2 = linalg.qr(a, mode='r')
assert_(r2.dtype == a_dtype)
assert_(isinstance(r2, a_type))
assert_almost_equal(r2, r1)
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