What does "Vectors must be the same lengths." mean?

I have been trying to adjust the code to have different values but it keeps messing up and I can't get anything to work. Here was the code:

    clear; load testtrace.mat

    subplot(2,1,1);

    plot(t,tracefar)

    title('1000 m offset');xlabel('seconds')

    subplot(2,1,2);

    plot(t,tracenear)

    title('10 m offset');xlabel('seconds')

    envfar = abs(hilbert(tracefar)); %compute Hilbert envelope

    envnear = abs(hilbert(tracenear)); %compute Hilbert envelope

    envdbfar=todb(envfar,max(envnear)); %decibel conversion

    envdbnear=todb(envnear); %decibel conversion

    figure

    plot(t,[envdbfar envdbnear],'b');xlabel('seconds');ylabel('decibels');

    grid;axis([0 3 -140 0])

and here is the error code that shows up:

>> Untitled2

Error using plot

Vectors must be the same lengths.

Error in Untitled2 (line 3)

plot(t,tracefar)

Answer 1

[Greg Heath]

Use the command

 whos

to check the dimensions of all the variables.

 Your error flag indicates that size(t) and size( tracefar) are not compatible for 

 plot(t, tracefar)

Hope this helps.

Thank you for formally accepting my answer

Greg

Answer 2

[Chad Greene]

I'm guessing that there's a variable in testtrace.mat called t, and another variable called tracefar. If you type length(t) into the command window, and then type length(tracefar) into the command window, you'll see that they are different numbers.

When you tell matlab to plot t and tracefar, Matlab needs to plot one y value (tracefar) for each x value (t). If x and y (or t and tracefar) do not have the same number of values, Matlab will get confused.

[Mehdi Fazilat]

Excellent, how we can make the same two different dimension variables? for example t=101 and E=102

[Walter Roberson]

L = min(length(t), length(E));
plot(t(1:L), E(1:L))