Nested for loop produces plot that is shifted horizontally

Hi, I want to set up a nested for loop to plot mRNA expression levels (y) over time (t) for different values of beta. y = 10 * beta (1 - exp(-t/10)).

time = [0 : 0.5 : 10]; 
beta = transpose([1 : 5]); 

y = zeros(5, 21); % initializing a matrix of zeros to store y values  

for time_point = 1 : length(time)
      for beta_val = beta 
          y(beta_val, time_point) = 10 * beta .* (1 - exp(-1/10 .* (time_point)));
      end
      plot(time, y);
  end

With this, I successfully get a plot, but it seems like the plot is shifted. y has to be zero for all plots at t=0.

Can someone tell me what I am doing wrong?

Answer 1

[sloppydisk]

You evaluated at the index of the timevector, rather than at the time itself. You could write time(time_point) instead to get the desired result. Or you could make just evaluate on a grid and avoid the loop altogether:

time = 0:0.5:10; 
beta = (1:5)'; 
y = 10 * beta * (1 - exp(-.1*time));
plot(time, y);

[positron96]

Thank you!