Plot vectors must be same length

fileName='ExtractedDataandGraphs.xlsx';
data=xlsread(fileName);

t=1.5; w=1.27; l=4.49;
A=w*t;

time=data(1:24,2);
u=0.449;
F=data(1:24,3);
sigma=F/A;

fig0=figure;
plot(time,F); xlabel('time (s)'); ylabel('Force (MPa)');

fig1=figure;
h11=subplot(3,1,1);
plot(time, sigma);
xlabel('time (s)'); ylabel('stress (MPa)');
title('Cartilage');

%removing ramp
[maxS, idxMax]=max(sigma);
t1=time(idxMax:end);
t1=t1-t1(1);
sigma1=sigma(idxMax:end);

fig2=figure;
h12=subplot(3,1,2);
plot(t1,sigma1); legend('sigma from data');
xlabel('time (s)'); ylabel('sigma (MPa)');

%variable creation
xdata=t1;
ydata=sigma1;

%fitting function
fun2fit=@(params, time) params(1)*exp(-params(2)*t1)+params(3);

%guess parameters
guess=[100,40,10];
funGuess=fun2fit(guess,time);
plot(time,funGuess);

I have tried everything and looked at so many other forums. I cannot figure out what is wrong with this and why ot wont complete the last plot function.

Answer 1

[Geoff Hayes]

K - the error is because of this line

 fun2fit=@(params, time) params(1)*exp(-params(2)*t1)+params(3);

Note how the second input parameter is time but you don't use it in the function. Rather you use t1 which is a 13x1 array. So the output of

 funGuess=fun2fit(guess,time);

is a 13x1 array which when trying to plot it against the 24x1 time array at

 plot(time,funGuess);

will lead to the above error. Just change your anonymous function to use time instead of t1

 fun2fit=@(params, time) params(1)*exp(-params(2)*time)+params(3);

[Image Analyst]

Or even better, call it something other than time since time() is a built-in function. I'd call it theTime or t instead.