# HG changeset patch
# User jwe
# Date 1138898992 0
# Node ID 5b80eaa366c127c5a3d535ea075c65154d197c86
# Parent  2857357f9d3cd31223f10ba9559de72839fd7fa9
[project @ 2006-02-02 16:49:52 by jwe]

diff --git a/scripts/ChangeLog b/scripts/ChangeLog
--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,3 +1,11 @@
+2006-02-02  John W. Eaton  <jwe@octave.org>
+
+	* plot/grid.m: Append ";\n" to "set grid" command.
+
+2006-02-02  A S Hodel  <hodelas@auburn.edu>
+
+	* control/base/rlocus.m: Don't atttempt to plot rlzer if it is empty.
+
 2006-01-13  John W. Eaton  <jwe@octave.org>
 
 	* audio/Makefile.in, control/base/Makefile.in,
diff --git a/scripts/control/base/rlocus.m b/scripts/control/base/rlocus.m
--- a/scripts/control/base/rlocus.m
+++ b/scripts/control/base/rlocus.m
@@ -74,7 +74,7 @@
 
   ## Convert the input to a transfer function if necessary
 
-  [num,den] = sys2tf(sys)               # extract numerator/denom polyomials
+  [num,den] = sys2tf(sys);               # extract numerator/denom polyomials
   lnum = length(num);      lden = length(den);
   if(lden < 2)
     error(sprintf("length of derivative=%d, doesn't make sense",lden));
@@ -217,9 +217,14 @@
         inname{1}, outname{1},gvec(1),gvec(ngain)));
     ylabel("Imag. axis");
 
-    plot(real(rlpolv),imag(rlpolv),".1;locus points;", ...
-        real(olpol),imag(olpol),"x2;open loop poles;", ...
-        real(rlzer),imag(rlzer),"o3;zeros;");
+    if(isempty(rlzer))
+      plot(real(rlpolv),imag(rlpolv),".1;locus points;", ...
+           real(olpol),imag(olpol),"x2;open loop poles;");
+    else
+      plot(real(rlpolv),imag(rlpolv),".1;locus points;", ...
+           real(olpol),imag(olpol),"x2;open loop poles;", ...
+           real(rlzer),imag(rlzer),"o3;zeros;");
+    endif
     rldata = [];
   endif
 endfunction
diff --git a/scripts/plot/grid.m b/scripts/plot/grid.m
--- a/scripts/plot/grid.m
+++ b/scripts/plot/grid.m
@@ -46,7 +46,7 @@
         __gnuplot_raw__ ("set nogrid;\n");
 	do_replot = true;
       elseif (strcmp ("on", x))
-        __gnuplot_raw__ ("set grid");
+        __gnuplot_raw__ ("set grid;\n");
 	do_replot = true;
       else
 	usage (usage_msg);