automatic signal summing and splitting (fix)

murrayrm · murrayrm · commit ada3eb2e8c72 · 2021-02-06T15:02:30.000-08:00
diff --git a/control/iosys.py b/control/iosys.py
@@ -2042,25 +2042,25 @@ def interconnect(syslist, connections=None, inplist=[], outlist=[],
         inplist = [inplist]
     new_inplist = []
     for signal in inplist:
+        # Create an empty connection and append to inplist
+        connection = []
+
         # Check for signal names without a system name
         if isinstance(signal, str) and len(signal.split('.')) == 1:
             # Get the signal name
             name = signal[1:] if signal[0] == '-' else signal
             sign = '-' if signal[0] == '-' else ""
 
             # Look for the signal name as a system input
-            new_name = None
             for sys in syslist:
                 if name in sys.input_index.keys():
-                    if new_name is not None:
-                        raise ValueError("signal %s is not unique" % name)
-                    new_name = sign + sys.name + "." + name
+                    connection.append(sign + sys.name + "." + name)
 
             # Make sure we found the name
-            if new_name is None:
+            if len(connection) == 0:
                 raise ValueError("could not find signal %s" % name)
             else:
-                new_inplist.append(new_name)
+                new_inplist.append(connection)
         else:
             new_inplist.append(signal)
     inplist = new_inplist
@@ -2070,25 +2070,25 @@ def interconnect(syslist, connections=None, inplist=[], outlist=[],
         outlist = [outlist]
     new_outlist = []
     for signal in outlist:
+        # Create an empty connection and append to inplist
+        connection = []
+
         # Check for signal names without a system name
         if isinstance(signal, str) and len(signal.split('.')) == 1:
             # Get the signal name
             name = signal[1:] if signal[0] == '-' else signal
             sign = '-' if signal[0] == '-' else ""
 
             # Look for the signal name as a system output
-            new_name = None
             for sys in syslist:
                 if name in sys.output_index.keys():
-                    if new_name is not None:
-                        raise ValueError("signal %s is not unique" % name)
-                    new_name = sign + sys.name + "." + name
+                    connection.append(sign + sys.name + "." + name)
 
             # Make sure we found the name
-            if new_name is None:
+            if len(connection) == 0:
                 raise ValueError("could not find signal %s" % name)
             else:
-                new_outlist.append(new_name)
+                new_outlist.append(connection)
         else:
             new_outlist.append(signal)
     outlist = new_outlist
diff --git a/control/tests/interconnect_test.py b/control/tests/interconnect_test.py
@@ -119,18 +119,14 @@ def test_interconnect_implicit():
     #     inputs=['r', '-y'], output='e', dimension=2)
     # S = control.interconnect([P, C, sumblk], inplist='r', outlist='y')
 
-    # Make sure that repeated inplist/outlist names generate an error
-    # Input not unique
-    Cbad = ct.tf2io(ct.tf(10, [1, 1]), inputs='r', outputs='x', name='C')
-    with pytest.raises(ValueError, match="not unique"):
-        Tio_sum = ct.interconnect(
-            (Cbad, P, sumblk), inplist=['r'], outlist=['y'])
-
-    # Output not unique
-    Cbad = ct.tf2io(ct.tf(10, [1, 1]), inputs='e', outputs='y', name='C')
-    with pytest.raises(ValueError, match="not unique"):
-        Tio_sum = ct.interconnect(
-            (Cbad, P, sumblk), inplist=['r'], outlist=['y'])
+    # Make sure that repeated inplist/outlist names work
+    pi_io = ct.interconnect(
+        (kp_io, ki_io), inplist=['e'], outlist=['u'])
+    pi_ss = ct.tf2ss(kp + ki)
+    np.testing.assert_almost_equal(pi_io.A, pi_ss.A)
+    np.testing.assert_almost_equal(pi_io.B, pi_ss.B)
+    np.testing.assert_almost_equal(pi_io.C, pi_ss.C)
+    np.testing.assert_almost_equal(pi_io.D, pi_ss.D)
 
     # Signal not found
     with pytest.raises(ValueError, match="could not find"):
