From c54097022899eaf51d8feb29637b26e663de88d1 Mon Sep 17 00:00:00 2001 From: Richard Murray Date: Fri, 19 Aug 2022 17:52:13 -0700 Subject: [PATCH] fix issue with slycot balred change in state --- control/tests/modelsimp_test.py | 48 +++++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 8 deletions(-) diff --git a/control/tests/modelsimp_test.py b/control/tests/modelsimp_test.py index 70e94dd91..0746e3fe2 100644 --- a/control/tests/modelsimp_test.py +++ b/control/tests/modelsimp_test.py @@ -182,17 +182,33 @@ def testBalredTruncate(self, matarrayin): B = matarrayin([[2.], [0.], [0.], [0.]]) C = matarrayin([[0.5, 0.6875, 0.7031, 0.5]]) D = matarrayin([[0.]]) + sys = StateSpace(A, B, C, D) orders = 2 rsys = balred(sys, orders, method='truncate') + Ar, Br, Cr, Dr = rsys.A, rsys.B, rsys.C, rsys.D + + # Result from MATLAB Artrue = np.array([[-1.958, -1.194], [-1.194, -0.8344]]) Brtrue = np.array([[0.9057], [0.4068]]) Crtrue = np.array([[0.9057, 0.4068]]) Drtrue = np.array([[0.]]) - np.testing.assert_array_almost_equal(rsys.A, Artrue, decimal=2) - np.testing.assert_array_almost_equal(rsys.B, Brtrue, decimal=4) - np.testing.assert_array_almost_equal(rsys.C, Crtrue, decimal=4) - np.testing.assert_array_almost_equal(rsys.D, Drtrue, decimal=4) + + # Look for possible changes in state in slycot + T1 = np.array([[1, 0], [0, -1]]) + T2 = np.array([[-1, 0], [0, 1]]) + T3 = np.array([[0, 1], [1, 0]]) + for T in (T1, T2, T3): + if np.allclose(T @ Ar @ T, Artrue, atol=1e-2, rtol=1e-2): + # Apply a similarity transformation + Ar, Br, Cr = T @ Ar @ T, T @ Br, Cr @ T + break + + # Make sure we got the correct answer + np.testing.assert_array_almost_equal(Ar, Artrue, decimal=2) + np.testing.assert_array_almost_equal(Br, Brtrue, decimal=4) + np.testing.assert_array_almost_equal(Cr, Crtrue, decimal=4) + np.testing.assert_array_almost_equal(Dr, Drtrue, decimal=4) @slycotonly def testBalredMatchDC(self, matarrayin): @@ -207,16 +223,32 @@ def testBalredMatchDC(self, matarrayin): B = matarrayin([[2.], [0.], [0.], [0.]]) C = matarrayin([[0.5, 0.6875, 0.7031, 0.5]]) D = matarrayin([[0.]]) + sys = StateSpace(A, B, C, D) orders = 2 rsys = balred(sys,orders,method='matchdc') + Ar, Br, Cr, Dr = rsys.A, rsys.B, rsys.C, rsys.D + + # Result from MATLAB Artrue = np.array( [[-4.43094773, -4.55232904], [-4.55232904, -5.36195206]]) Brtrue = np.array([[1.36235673], [1.03114388]]) Crtrue = np.array([[1.36235673, 1.03114388]]) Drtrue = np.array([[-0.08383902]]) - np.testing.assert_array_almost_equal(rsys.A, Artrue, decimal=2) - np.testing.assert_array_almost_equal(rsys.B, Brtrue, decimal=4) - np.testing.assert_array_almost_equal(rsys.C, Crtrue, decimal=4) - np.testing.assert_array_almost_equal(rsys.D, Drtrue, decimal=4) + + # Look for possible changes in state in slycot + T1 = np.array([[1, 0], [0, -1]]) + T2 = np.array([[-1, 0], [0, 1]]) + T3 = np.array([[0, 1], [1, 0]]) + for T in (T1, T2, T3): + if np.allclose(T @ Ar @ T, Artrue, atol=1e-2, rtol=1e-2): + # Apply a similarity transformation + Ar, Br, Cr = T @ Ar @ T, T @ Br, Cr @ T + break + + # Make sure we got the correct answer + np.testing.assert_array_almost_equal(Ar, Artrue, decimal=2) + np.testing.assert_array_almost_equal(Br, Brtrue, decimal=4) + np.testing.assert_array_almost_equal(Cr, Crtrue, decimal=4) + np.testing.assert_array_almost_equal(Dr, Drtrue, decimal=4) pFad - Phonifier reborn

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