# Sample 2-d plot

# You can run this by typing at the prompt: octave -q 2dplot.m

# Set some basic parameters, including the name of the
# output data file.

outfile = "2dplot.dat";
global a = 1;
z_vec = linspace(1, 5, 100);

# "quad" is octave's integration function. You can type
# "help quad" and "help quad_options" in octave for help.

function r = f(x)
  global z;
  r = 2*sin(x).*sqrt((z + sin(x)));
endfunction

function r = F()
  global a;
  r = quad("f", -pi/2, a);
endfunction

# The main loop.

points = [];
global z;
for z = z_vec
  points = [points z sin(z)*F()/(z + sin(a))**(3/2)];
endfor

# Save the data to a file and exit. The output format
# is very simple (two columns) and appropriate for gnuplot.

fd = fopen(outfile, "wt");
fprintf(fd, "%14.6f %14.6f\n", points);
fclose(fd);
disp("Done!");