how to make a plot smooth

How to smooth a plot?

len1 = [25, 250, 500, 750, 1000];
  for k1 = 1:length(len1)
      standard_deviation1(k1) = std(resdphs(1:5000, len1(k1)));
  end

    f10 = [110, 100, 90, 80, 70];
    figure(3),plot(f10, standard_deviation1);xlabel('frequency'); ylabel('standarddev');
    grid

[Adam]

Your plot seems to bear no relation to the code that comes with it.

[Mayank Lakhani]

Hey, Adam sorry for my mistake.

Answer 1

[Star Strider]

I’m not certain what you want to do, but you might consider experimenting with polyfit and its friends.

[Mayank Lakhani]

I mean there shoud be no sharp edges in the curve, so it shoud be bending smoothly.

[Star Strider]

The polyfit function can do that, as can the interp1 function with one of the nonlinear method choices, such as 'spline', 'pchip' or 'cubic'.

If you want the curve defined at more points than you measured, also use the linspace function. For example, to get a vector of 100 points over the range of your ‘f10’ vector, consider creating ‘f10_interp’ (call it what you want) as:

f10_interp = linspace(min(f10), max(f10));

then to use it with interp1:

stdev1_interp = interp1(f10, standard_deviation1, f10_interp, 'spline');

and plot it as:

plot(f10_interp, stdev1_interp)

NOTE: Since I don’t have your data, this is UNTESTED CODE.

Experiment with it to get the result you want.

[Mayank Lakhani]

Hey Star Strider, thanks it is working :)

[Star Strider]

My pleasure!