change system name when converting tf to ss

murrayrm · murrayrm · commit 37243f618c6e · 2023-06-03T14:53:23.000-07:00
diff --git a/control/iosys.py b/control/iosys.py
@@ -2395,7 +2395,9 @@ def ss(*args, **kwargs):
                      "non-unique state space realization")
 
             # Create a state space system from an LTI system
-            sys = LinearIOSystem(_convert_to_statespace(sys), **kwargs)
+            sys = LinearIOSystem(
+                _convert_to_statespace(sys, use_prefix_suffix=True), **kwargs)
+
         else:
             raise TypeError("ss(sys): sys must be a StateSpace or "
                             "TransferFunction object.  It is %s." % type(sys))
diff --git a/control/statesp.py b/control/statesp.py
@@ -1519,7 +1519,7 @@ def output(self, t, x, u=None, params=None):
 
 
 # TODO: add discrete time check
-def _convert_to_statespace(sys):
+def _convert_to_statespace(sys, use_prefix_suffix=False):
     """Convert a system to state space form (if needed).
 
     If sys is already a state space, then it is returned.  If sys is a
@@ -1556,11 +1556,10 @@ def _convert_to_statespace(sys):
                            denorder, den, num, tol=0)
 
             states = ssout[0]
-            return StateSpace(
+            newsys = StateSpace(
                 ssout[1][:states, :states], ssout[2][:states, :sys.ninputs],
-                ssout[3][:sys.noutputs, :states], ssout[4], sys.dt,
-                inputs=sys.input_labels, outputs=sys.output_labels,
-                name=sys.name)
+                ssout[3][:sys.noutputs, :states], ssout[4], sys.dt)
+
         except ImportError:
             # No Slycot.  Scipy tf->ss can't handle MIMO, but static
             # MIMO is an easy special case we can check for here
@@ -1585,9 +1584,13 @@ def _convert_to_statespace(sys):
                 # the squeeze
                 A, B, C, D = \
                     sp.signal.tf2ss(squeeze(sys.num), squeeze(sys.den))
-                return StateSpace(
-                    A, B, C, D, sys.dt, inputs=sys.input_labels,
-                    outputs=sys.output_labels, name=sys.name)
+                newsys = StateSpace(A, B, C, D, sys.dt)
+
+        # Copy over the signal (and system) names
+        newsys._copy_names(
+            sys,
+            prefix_suffix_name='converted' if use_prefix_suffix else None)
+        return newsys
 
     elif isinstance(sys, FrequencyResponseData):
         raise TypeError("Can't convert FRD to StateSpace system.")
@@ -1600,7 +1603,6 @@ def _convert_to_statespace(sys):
     except Exception:
         raise TypeError("Can't convert given type to StateSpace system.")
 
-
 # TODO: add discrete time option
 def _rss_generate(
         states, inputs, outputs, cdtype, strictly_proper=False, name=None):
@@ -1914,7 +1916,8 @@ def tf2ss(*args, **kwargs):
         if not isinstance(sys, TransferFunction):
             raise TypeError("tf2ss(sys): sys must be a TransferFunction "
                             "object.")
-        return StateSpace(_convert_to_statespace(sys), **kwargs)
+        return StateSpace(_convert_to_statespace(sys, use_prefix_suffix=True),
+                          **kwargs)
     else:
         raise ValueError("Needs 1 or 2 arguments; received %i." % len(args))
 
diff --git a/control/tests/namedio_test.py b/control/tests/namedio_test.py
@@ -169,6 +169,9 @@ def test_io_naming(fun, args, kwargs):
         assert sys_ss != sys_r
         assert sys_ss.input_labels == input_labels
         assert sys_ss.output_labels == output_labels
+        if not isinstance(sys_r, ct.StateSpace):
+            # System should get unique name
+            assert sys_ss.name != sys_r.name
 
         # Reassign system and signal names
         sys_ss = ct.ss(
@@ -247,11 +250,11 @@ def test_convert_to_statespace():
 
     # check that name, inputs, and outputs passed through
     sys_new = ct.ss(sys)
-    assert sys_new.name == 'sys'
+    assert sys_new.name == 'sys$converted'
     assert sys_new.input_labels == ['u']
     assert sys_new.output_labels == ['y']
     sys_new = ct.ss(sys_static)
-    assert sys_new.name == 'sys_static'
+    assert sys_new.name == 'sys_static$converted'
     assert sys_new.input_labels == ['u']
     assert sys_new.output_labels == ['y']
 
