[Octave-cvsupdate] SF.net SVN: octave:[8505] trunk/octave-forge/main/control/inst

[<par...@us...>]

Revision: 8505
          http://octave.svn.sourceforge.net/octave/?rev=8505&view=rev
Author:   paramaniac
Date:     2011-09-06 06:03:10 +0000 (Tue, 06 Sep 2011)
Log Message:
-----------
control: improve argument checking, add a test

Modified Paths:
--------------
    trunk/octave-forge/main/control/inst/@lti/c2d.m
    trunk/octave-forge/main/control/inst/@lti/d2c.m
    trunk/octave-forge/main/control/inst/ltimodels.m

Modified: trunk/octave-forge/main/control/inst/@lti/c2d.m
===================================================================
--- trunk/octave-forge/main/control/inst/@lti/c2d.m	2011-09-05 21:03:51 UTC (rev 8504)
+++ trunk/octave-forge/main/control/inst/@lti/c2d.m	2011-09-06 06:03:10 UTC (rev 8505)
@@ -24,7 +24,7 @@
 ## @strong{Inputs}
 ## @table @var
 ## @item sys
-## Continuous-time LTI model.
+## Continuous-time LTI model.  Only state-space models have been implemented so far.
 ## @item tsam
 ## Sampling time in seconds.
 ## @item method
@@ -73,6 +73,10 @@
     error ("c2d: third argument is not a string");
   endif
 
+  if (! issample (w0, 0))
+    error ("c2d: fourth argument is not a valid pre-warping frequency");
+  endif
+
   sys = __c2d__ (sys, tsam, lower (method), w0);
   sys.tsam = tsam;
 

Modified: trunk/octave-forge/main/control/inst/@lti/d2c.m
===================================================================
--- trunk/octave-forge/main/control/inst/@lti/d2c.m	2011-09-05 21:03:51 UTC (rev 8504)
+++ trunk/octave-forge/main/control/inst/@lti/d2c.m	2011-09-06 06:03:10 UTC (rev 8505)
@@ -24,7 +24,7 @@
 ## @strong{Inputs}
 ## @table @var
 ## @item sys
-## Discrete-time LTI model.
+## Discrete-time LTI model.  Only state-space models have been implemented so far.
 ## @item method
 ## Optional conversion method.  If not specified, default method @var{"zoh"}
 ## is taken.
@@ -67,6 +67,10 @@
     error ("d2c: second argument is not a string");
   endif
 
+  if (! issample (w0, 0))
+    error ("d2c: third argument is not a valid pre-warping frequency");
+  endif
+
   sys = __d2c__ (sys, sys.tsam, lower (method), w0);
   sys.tsam = 0;
 

Modified: trunk/octave-forge/main/control/inst/ltimodels.m
===================================================================
--- trunk/octave-forge/main/control/inst/ltimodels.m	2011-09-05 21:03:51 UTC (rev 8504)
+++ trunk/octave-forge/main/control/inst/ltimodels.m	2011-09-06 06:03:10 UTC (rev 8505)
@@ -1346,3 +1346,26 @@
 %!
 %!assert (Mo, Me, 1e-4);
 
+
+## bilinear transformation with pre-warping
+## both directions
+%!shared Mo, Me
+%! A = [  1.0  0.5
+%!        0.5  1.0 ];
+%!
+%! B = [  0.0 -1.0
+%!        1.0  0.0 ];
+%!
+%! C = [ -1.0  0.0
+%!        0.0  1.0 ];
+%!
+%! D = [  1.0  0.0
+%!        0.0 -1.0 ];
+%!
+%! [Ao, Bo, Co, Do] = ssdata (d2c (c2d (ss (A, B, C, D), 2, "prewarp", 1000), "prewarp", 1000));
+%!
+%! Mo = [Ao, Bo; Co, Do];
+%! Me = [A, B; C, D];
+%!
+%!assert (Mo, Me, 1e-4);
+

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