address @sawyerbfuller review comments

murrayrm · murrayrm · commit b338e32e95ec · 2021-01-18T08:31:41.000-08:00
diff --git a/control/frdata.py b/control/frdata.py
@@ -441,10 +441,10 @@ def __call__(self, s, squeeze=None):
             frequency values.
         """
         # Make sure that we are operating on a simple list
-        if len(np.array(s, ndmin=1).shape) > 1:
+        if len(np.atleast_1d(s).shape) > 1:
             raise ValueError("input list must be 1D")
 
-        if any(abs(np.array(s, ndmin=1).real) > 0):
+        if any(abs(np.atleast_1d(s).real) > 0):
             raise ValueError("__call__: FRD systems can only accept "
                             "purely imaginary frequencies")
 
diff --git a/control/statesp.py b/control/statesp.py
@@ -646,10 +646,6 @@ def __call__(self, x, squeeze=None):
         Returns the complex frequency response `sys(x)` where `x` is `s` for
         continuous-time systems and `z` for discrete-time systems.
 
-        In general the system may be multiple input, multiple output
-        (MIMO), where `m = self.inputs` number of inputs and `p =
-        self.outputs` number of outputs.
-
         To evaluate at a frequency omega in radians per second, enter
         ``x = omega * 1j``, for continuous-time systems, or
         ``x = exp(1j * omega * dt)`` for discrete-time systems. Or use
