Fix regressions caused by ismatrix definition change (partial fix bug #47036). * inputdlg.m: Test that linespec isnumeric. * uigetfile.m: Check that position property value isnumeric. * fminunc.m: Check that x0 isnumeric. * fsolve.m: Check that x0 isnumeric. * lsqnonneg.m: Check that inputs C & D are both isnumeric and ismatrix. * pqpnonneg.m: Check that inputs C & D are both isnumeric and ismatrix. * bicg.m: Check input A issquare. Rephrase error messages. * bicgstab.m: Check input A issquare. Rephrase error messages. * cgs.m: Check input A issquare. Rephrase error messages. * gmres.m: Check input A issquare. Rephrase error messages. Change BIST test to match new error message. * qmr.m: Check input A issquare. Rephrase error messages. * spconvert.m: Check nargin first. Simplify input validation. Wrap long error message to < 80 chars. * treeplot.m: Simplify input validation.

--- a/scripts/sparse/spconvert.m	Sat Jan 30 07:55:18 2016 -0800
+++ b/scripts/sparse/spconvert.m	Mon Feb 01 22:59:43 2016 -0800
@@ -30,13 +30,18 @@
 
 function s = spconvert (m)
 
+  if (nargin != 1)
+    print_usage ();
+  endif
+
   if (issparse (m))
     s = m;
   else
     sz = size (m);
-    if (nargin != 1 || ! ismatrix (m) || ! isreal (m)
+    if (! ismatrix (m) || ! isreal (m)
         || length (sz) != 2 || (sz(2) != 3 && sz(2) != 4))
-      error ("spconvert: argument must be sparse or real matrix with 3 or 4 columns");
+      error (["spconvert: argument must be sparse or real matrix" ...
+              "with 3 or 4 columns"]);
     elseif (sz(2) == 3)
       s = sparse (m(:,1), m(:,2), m(:,3));
     else