From 2959df89df338a24b7ef420da0c920c7e883f3d1 Mon Sep 17 00:00:00 2001 From: mp4096 Date: Fri, 20 May 2016 20:39:11 +0200 Subject: [PATCH 1/2] Working towards #84 and #85 Also changed the check for matrix singularity --- control/statesp.py | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/control/statesp.py b/control/statesp.py index 1f5e09ccd..80da2a5f8 100644 --- a/control/statesp.py +++ b/control/statesp.py @@ -55,7 +55,7 @@ dot, empty, exp, eye, matrix, ones, pi, poly, poly1d, roots, shape, sin, \ zeros, squeeze from numpy.random import rand, randn -from numpy.linalg import inv, det, solve +from numpy.linalg import solve, eigvals, matrix_rank from numpy.linalg.linalg import LinAlgError from scipy.signal import lti, cont2discrete # from exceptions import Exception @@ -405,7 +405,7 @@ def freqresp(self, omega): def pole(self): """Compute the poles of a state space system.""" - return roots(poly(self.A)) + return eigvals(self.A) def zero(self): """Compute the zeros of a state space system.""" @@ -452,21 +452,24 @@ def feedback(self, other=1, sign=-1): D2 = other.D F = eye(self.inputs) - sign * D2 * D1 - if abs(det(F)) < 1.e-6: + if matrix_rank(F) != self.inputs: raise ValueError("I - sign * D2 * D1 is singular.") - E = inv(F) - T1 = eye(self.outputs) + sign * D1 * E * D2 - T2 = eye(self.inputs) + sign * E * D2 * D1 + # Precompute F\D2 and F\C2 (E = inv(F)) + E_D2 = solve(F, D2) + E_C2 = solve(F, C2) + + T1 = eye(self.outputs) + sign * D1 * E_D2 + T2 = eye(self.inputs) + sign * E_D2 * D1 A = concatenate( (concatenate( - (A1 + sign * B1 * E * D2 * C1, sign * B1 * E * C2), axis=1), + (A1 + sign * B1 * E_D2 * C1, sign * B1 * E_C2), axis=1), concatenate( - (B2 * T1 * C1, A2 + sign * B2 * D1 * E * C2), axis=1)), + (B2 * T1 * C1, A2 + sign * B2 * D1 * E_C2), axis=1)), axis=0) B = concatenate((B1 * T2, B2 * D1 * T2), axis=0) - C = concatenate((T1 * C1, sign * D1 * E * C2), axis=1) + C = concatenate((T1 * C1, sign * D1 * E_C2), axis=1) D = D1 * T2 return StateSpace(A, B, C, D, dt) From 6aee19452adfdb4059d8d48e396ee6b66dac8020 Mon Sep 17 00:00:00 2001 From: mp4096 Date: Fri, 20 May 2016 21:05:46 +0200 Subject: [PATCH 2/2] Added sorting of poles to the state-space unit test --- control/tests/statesp_test.py | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/control/tests/statesp_test.py b/control/tests/statesp_test.py index 0c969b1e1..c19f4f38b 100644 --- a/control/tests/statesp_test.py +++ b/control/tests/statesp_test.py @@ -32,12 +32,13 @@ def setUp(self): def testPole(self): """Evaluate the poles of a MIMO system.""" - p = self.sys1.pole() - - np.testing.assert_array_almost_equal(p, [3.34747678408874, + p = np.sort(self.sys1.pole()) + true_p = np.sort([3.34747678408874, -3.17373839204437 + 1.47492908003839j, -3.17373839204437 - 1.47492908003839j]) + np.testing.assert_array_almost_equal(p, true_p) + def testZero(self): """Evaluate the zeros of a SISO system.""" pFad - Phonifier reborn

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