Problem in plotting using semilogx() function

I need to plot a graph between w(frequency) and Mdb(Magnitude in db) using semilogx() function for different values of w. The output of graph is null. It shows nothing and there are no errors displayed. Where did I go wrong.

R=zeros(1,10000);
I=zeros(1,10000);
Mag=zeros(1,10000);
Z=zeros(1,10000);
Y=zeros(1,10000);
Mdb=zeros(1,10000);
for *w* = 0.1:0.01:10
R=(256-(16*w^2))/((16-(w^2))^2+(10*w)^2);
I=-160*w/((16-w^2)^2+(10*w)^2);
Mag=sqrt(R^2+I^2);
Z=atan2(I,R);
Y=Z*180/pi;
*Mdb* =20*log10(Mag); *bold*
plot(w,Mdb,'g');
semilogx(w,Mdb);
end

Answer 1

[Rick Rosson]

Vectorized code, no for-loop necessary:

   w = 0.1:0.01:10;
   R = (256-(16*w.^2))./((16-(w.^2)).^2+(10*w).^2);
   I = -160*w./((16-w.^2).^2+(10*w).^2);
   X = complex(R,I);
   Mag = abs(X);
   Mdb = 20*log10(Mag);
   phi = angle(X)*180/pi;

   figure;

   ax(1) = subplot(2,1,1);
   semilogx(w,Mdb);
   grid on;
   xlabel('Frequency');
   ylabel('Magnitude in dB');

   ax(2) = subplot(2,1,2);
   semilogx(w,phi);
   grid on;
   xlabel('Frequency');
   ylabel('Phase angle in degrees');

   linkaxes(ax,'x');