To plot some data with a minimum of effort do:
> data = (0:pi:.1)'; > data[;2] = cos (2*pi*data*3); > pstart (,,"xwin"); > plot (data);
The pstart
function was called with the default sub-plot
definition (1 subplot), and the X-windows driver as the display
device. The plot
function accepts matrices, or lists as
arguments and plots the columns of a matrix, or the columns of each
matrix of a list.
Now for a slightly more complex example.
> t = (0:10:.05)'; > x = exp (-0.5*t) .* (cos (2*pi*3*t) + sin (2*pi*7*t)); > X = fft (x); > rfile faxis > freq = faxis (X, .05, 3); > mag = abs (X); > rfile angle > phase = angle (X); > pstart (1,2,"xwin"); > > ptitle ("Magnitude of FFT") > xlabel ("Frequency (Hertz)"); > plot ([freq,mag]); > > ptitle ("Angle (atan2(imag/real)) of FFT") > xlabel ("Frequency (Hertz)"); > ylabel ("Angle (radians)"); > plot ([freq,phase]); > plprint ("p3.ps");
In this example we create a plot-window with two subplots so that
we can display related information on the same plot-window. The
arguments to pstart
specify that there will be 1 plot in the
horizontal direction, and 2 plots in the vertical direction, thus
creating 2 sub-plots. The first ptitle
and xlabel
function calls effect the first sub-plot. The first call to
plot
creates the first sub-plot. The subsequent calls to
ptitle
, xlabel
and ylabel
effect the second
sub-plot, and the last call to plot
creates the second
sub-plot.
The last line is a call to plprint
. The plprint
function creates a file that contains a copy of the contents of the
current plot-window. The default hardcopy device for plprint
is Postscript, but color Postscipt, Xfig, plmeta, and HP-LJII can
also be specified. The output from plprint
is presented in
Figure .