Dear Octave Community,
How can I make xlabel('Frequency [rad/s]') visible on a plot? The
plot
window seems to be too small. I'm using Octave 3.2.0 on Mac OS X
10.5.7 with GnuPlot 4.2.5 and AquaTerm 1.0.1. Thanks for any help.
Regards,
Lukas
EXAMPLE M-FILE:
% Heat Exchanger
% Tabula Rasa
clear all;
close all;
clc;
% Physical Parameters
m_star_1 = 0.5; % kg/s
m_star_2 = 0.2; % kg/s
V_1 = 0.01; % m^3
V_2 = 0.02; % m^3
rho = 1000; % kg/m^3
c = 4200; % J/(kg K)
Ar = 2; % m^2
k = 2000; % W/(m^2 K)
% Control-Oriented Parameters
tau_1 = rho * V_1 * c / ( m_star_1 * c + k * Ar );
tau_2 = rho * V_2 * c / ( m_star_2 * c + k * Ar );
sigma_1 = k * Ar / ( m_star_1 * c + k * Ar );
sigma_2 = k * Ar / ( m_star_2 * c + k * Ar );
beta_1 = m_star_1 * c / ( m_star_1 * c + k * Ar );
beta_2 = m_star_2 * c / ( m_star_2 * c + k * Ar );
% System Matrices
A = [ -1/tau_1 sigma_1/tau_1 ;
sigma_2/tau_2 -1/tau_2 ];
B = [ beta_1/tau_1 0 ;
0 beta_2/tau_2 ];
C = [ 1 0 ;
0 1 ];
D = [ 0 0 ;
0 0 ];
% State Space Form
sys = ss(A,B,C,D);
% Stability
eigw = eig(A)
% Controllability
co = ctrb(A,B);
r_co = rank(co)
% Observability
ob = obsv(A,C);
r_ob = rank(ob)
% Singular Value Plot
w = logspace(-3, 1, 1000); % rad/s
for k = 1 : size(w, 2)
% Frequency Response Matrix
P = C * inv(i * w(k) * eye(size(A)) - A) * B + D;
% Singular Value Decomposition
sigma = svd(P);
sigma_max(k) = max(sigma);
sigma_min(k) = min(sigma);
end
figure(1)
semilogx(w, 20*log10(sigma_max), w, 20*log10(sigma_min))
xlabel('Frequency [rad/s]')
ylabel('Singular Values [dB]')
grid on
Octave uses gnuplot to render its figures. Gnuplot's output looks a
bit different depending upon the "terminal" you use. I expect you
are currently using Aquaterm.
You might try using x11 (x11 should be in your utilities folder) ...
close all
setenv ("GNUTERM", "x11")
plot (1:10)
xlabel ("my xlabel")
or (if you have it installed) try wxt
close all
setenv ("GNUTERM", "wxt")
plot (1:10)
xlabel ("my xlabel")
The one sure way to get what you want is to change the default
position of the plot box.
close all
set (0, "defaultaxesposition", [0.13, 0.13, 0.775, 0.795])
plot (1:10)
xlabel ("my xlabel")
Ben