[Plplot-general] Problems plotting

[Frederick G. <fg...@no...>]

Howdy,

   I am trying to make a 3d plot and having troubles.  I have read through the online
documentation and chunks of the plplot code base.  Here is my trouble.  I have some code
that solves the heat eq. via forward euler and returns the array u[X][T] , 0 < x < pi , and
0 < t < 10.0.  Of course this values for u are between 0 and 1.  I plotted the matrix in
gnuplot and got the correct normaly lookin' graph so the solution looks correct. The number 
of x sample points is J and the number of t sample points is N.  

I use the code (probably incorrect to plot)

plsdev("xwin");
plinit();
	
plenv(0.0, 12.0, 0.0, 10.0, 0, 0); // Viewport is entire subpage
	
// Set window characteristics
	
plw3d(2.0, 4.0, 3.0, -3.5, 3.5, -10.0, 10.0, -2.0, 2.0, 45.0, 30.0);
plot3d(xc, tc, u, J, N, 3, 0);
	
sleep(10);
	
plend(); 

And the plot that comes up is a big mess of lines.  Interestingly if I recompile and add
the configure switch --with-double this refuses to plot at all with the errors

*** PLPLOT ERROR ***
plenv: Invalid xmin and xmax arguments, aborting operation

*** PLPLOT ERROR ***
plw3d: Please set up 2-d window first, aborting operation

*** PLPLOT ERROR ***
plot3dc: Please set up window first, aborting operation

I have used 5.1.0, 5.2.0, and cvs with similar results.  The environment is:

OS: Linux
LIBC: glibc 2.3.1

What sections of the documentation should I read?  What am I doing wrong

Thanks,
Fred

-- 
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