change system name when converting ss to tf

murrayrm · murrayrm · commit 0530b52f87f5 · 2023-06-03T15:15:13.000-07:00
diff --git a/control/namedio.py b/control/namedio.py
@@ -119,13 +119,11 @@ def _copy_names(self, sys, prefix="", suffix="", prefix_suffix_name=None):
         self.name = prefix + sys.name + suffix
 
         # Name the inputs, outputs, and states
-        self.ninputs, self.input_index = \
-            sys.ninputs, sys.input_index.copy()
-        self.noutputs, self.output_index = \
-            sys.noutputs, sys.output_index.copy()
-        if sys.nstates:         # only copy for state space systems
-            self.nstates, self.state_index = \
-                sys.nstates, sys.state_index.copy()
+        self.input_index = sys.input_index.copy()
+        self.output_index = sys.output_index.copy()
+        if self.nstates and sys.nstates:
+            # only copy state names for state space systems
+            self.state_index = sys.state_index.copy()
 
     def copy(self, name=None, use_prefix_suffix=True):
         """Make a copy of an input/output system
diff --git a/control/tests/xferfcn_test.py b/control/tests/xferfcn_test.py
@@ -1262,6 +1262,12 @@ def test_copy_names(create, args, kwargs, convert):
     if cpy.nstates is not None and sys.nstates is not None:
         assert cpy.state_labels == sys.state_labels
 
+    # Make sure that names aren't the same if system changed type
+    if not isinstance(cpy, create):
+        assert cpy.name == sys.name + '$converted'
+    else:
+        assert cpy.name == sys.name
+
     # Relabel inputs and outputs
     cpy = convert(sys, inputs='myin', outputs='myout')
     assert cpy.input_labels == ['myin']
diff --git a/control/xferfcn.py b/control/xferfcn.py
@@ -1433,7 +1433,8 @@ def _add_siso(num1, den1, num2, den2):
     return num, den
 
 
-def _convert_to_transfer_function(sys, inputs=1, outputs=1):
+def _convert_to_transfer_function(
+        sys, inputs=1, outputs=1, use_prefix_suffix=False):
     """Convert a system to transfer function form (if needed).
 
     If sys is already a transfer function, then it is returned.  If sys is a
@@ -1509,7 +1510,10 @@ def _convert_to_transfer_function(sys, inputs=1, outputs=1):
                 num = squeeze(num)  # Convert to 1D array
                 den = squeeze(den)  # Probably not needed
 
-        return TransferFunction(num, den, sys.dt)
+        newsys = TransferFunction(num, den, sys.dt)
+        if use_prefix_suffix:
+            newsys._copy_names(sys, prefix_suffix_name='converted')
+        return newsys
 
     elif isinstance(sys, (int, float, complex, np.number)):
         num = [[[sys] for j in range(inputs)] for i in range(outputs)]
@@ -1809,7 +1813,8 @@ def ss2tf(*args, **kwargs):
             if not kwargs.get('outputs'):
                 kwargs['outputs'] = sys.output_labels
             return TransferFunction(
-                _convert_to_transfer_function(sys), **kwargs)
+                _convert_to_transfer_function(sys, use_prefix_suffix=True),
+                **kwargs)
         else:
             raise TypeError(
                 "ss2tf(sys): sys must be a StateSpace object.  It is %s."
