Merge pull request #253 from murrayrm/fix_lqr_badarg

murrayrm · web-flow · commit 4eb485f61743 · 2018-12-21T19:08:17.000-08:00
Fix Travis CI failure (lqr bad argument)
diff --git a/control/statesp.py b/control/statesp.py
@@ -385,7 +385,7 @@ def evalfr(self, omega):
         with input value s = i * omega.
 
         """
-        warn("StateSpace.evalfr(omega) will be depracted in a future "
+        warn("StateSpace.evalfr(omega) will be deprecated in a future "
              "release of python-control; use evalfr(sys, omega*1j) instead",
              PendingDeprecationWarning)
         return self._evalfr(omega)
diff --git a/control/tests/matlab_test.py b/control/tests/matlab_test.py
@@ -414,6 +414,14 @@ def testAcker(self):
     @unittest.skipIf(not slycot_check(), "slycot not installed")
     def testLQR(self):
         (K, S, E) = lqr(self.siso_ss1.A, self.siso_ss1.B, np.eye(2), np.eye(1))
+
+        # Should work if [Q N;N' R] is positive semi-definite
+        (K, S, E) = lqr(self.siso_ss2.A, self.siso_ss2.B, 10*np.eye(3), \
+                            np.eye(1), [[1], [1], [2]])
+
+    @unittest.skip("check not yet implemented")
+    def testLQR_checks(self):
+        # Make sure we get a warning if [Q N;N' R] is not positive semi-definite
         (K, S, E) = lqr(self.siso_ss2.A, self.siso_ss2.B, np.eye(3), \
                             np.eye(1), [[1], [1], [2]])
 
