Fix h2syn, added simple test

roryyorke · roryyorke · commit 81b8a5b1292c · 2016-06-27T18:59:37.000+02:00
Similar fix to hinfsyn: np -&gt; np_, and identical test.
diff --git a/control/robust.py b/control/robust.py
@@ -90,8 +90,8 @@ def h2syn(P,nmeas,ncon):
 
     n = np.size(P.A,0)
     m = np.size(P.B,1)
-    np = np.size(P.C,0)
-    out = sb10hd(n,m,np,ncon,nmeas,P.A,P.B,P.C,P.D)
+    np_ = np.size(P.C,0)
+    out = sb10hd(n,m,np_,ncon,nmeas,P.A,P.B,P.C,P.D)
     Ak = out[0]
     Bk = out[1]
     Ck = out[2]
diff --git a/control/tests/robust_test.py b/control/tests/robust_test.py
@@ -26,6 +26,21 @@ def testHinfsyn(self):
 
     # TODO: add more interesting examples
 
+class TestH2(unittest.TestCase):
+    @unittest.skipIf(not slycot_check(), "slycot not installed")
+    def testH2syn(self):
+        "Test h2syn"
+        p = control.ss(-1, [1, 1], [[1], [1]], [[0, 1], [1, 0]])
+        k = control.robust.h2syn(p, 1, 1)
+        # from Octave, which also uses SB10HD for H-2 synthesis:
+        #   a= -1; b1= 1; b2= 1; c1= 1; c2= 1; d11= 0; d12= 1; d21= 1; d22= 0;
+        #   g = ss(a,[b1,b2],[c1;c2],[d11,d12;d21,d22]);
+        #   k = h2syn(g,1,1);
+        # the solution is the same as for the hinfsyn test
+        np.testing.assert_array_almost_equal(k.A, [[-3]])
+        np.testing.assert_array_almost_equal(k.B, [[1]])
+        np.testing.assert_array_almost_equal(k.C, [[-1]])
+        np.testing.assert_array_almost_equal(k.D, [[0]])
 
 if __name__ == "__main__":
     unittest.main()
