@@ -1785,46 +1785,48 @@ def ab13md(Z, nblock, itype, x=None):
 
     Parameters
     ----------
-    Z : (n,n) complex array
+    Z : (n, n) array_like
       Matrix to find structured singular value upper bound of
 
-    nblock : (m,) integer array
+    nblock : (m,) array_like
       The size of the block diagonals of the uncertainty structure;
       i.e., nblock(i)=p means that the ith block is pxp.
 
-    itype : (m,) integer array
+    itype : (m,) array_like
       The type of each block diagonal uncertainty defined in nblock.
       itype(i)==1 means that the ith block is real, while itype(i)==2
       means the the ith block is complex.  Real blocks must be 1x1,
       i.e., if itype(i)==1, nblock(i) must be 1.
 
-    x : (q,) real array or None
+    x : (q,) array_like, optional
       If not None, must be the output of a previous call to ab13md.
       The previous call must have been with the same values of n,
       nblock, and itype; and the previous call's Z should be "close"
       to the current call's Z.
 
       q is determined by the block structure; see SLICOT AB13MD for
-      details.
+      details. Default is None.
 
     Returns
     -------
     mubound : non-negative real scalar
       Upper bound on structure singular value for given arguments
 
-    d, g : (n,) real arrays
+    d, g : (n,) ndarray
       Real arrays such that if D=np.diag(g), G=np.diag(G), and ZH = Z.T.conj(), then
         ZH @ D**2 @ Z + 1j * (G@Z - ZH@G) - mu**2 * D**2
       will be negative semi-definite.
 
-    xout : (q,) real array
+    xout : (q,) ndarray
       For use as ``x`` argument in subsequent call to ``ab13md``.
 
     For scalar Z and real uncertainty (ntype=1, itype=1), returns 0
     instead of abs(Z).
 
     Raises
     ------
+    SlycotParameterError
+        :info = -i: the i-th argument had an illegal value
     SlycotArithmeticError
         :info = 1: Block sizes must be positive
         :info = 2: Block sizes must sum to n