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Matlab code for summation?

  1. Apr 26, 2009 #1
    i need to write this into matlab

    http://www.engin.umich.edu/class/bme456/ch10fitbiphasic/biphasfit19.gif [Broken]

    which i have done here:

    uj = (-sig/Ha)*(xj-(((2*h)/(pi^2))*((((-1)^n)/((n+1/2)^(1/2)))*sin((n+1/2)*((pi*xj)/h))*exp(((-Ha*ko)/(h^2))*((n+1/2)^2)*(pi^2)*t))));

    how do i vary n, and get the equation to sum over n=0-3? and then again from n=0-100?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Apr 26, 2009 #2
    Call everything inside the summation f(n)

    for i=1:4 %n from 0 to 3 case
    y(i) = f(i-1)
    end

    sum(y);

    for i=1:101 %n from 0 to 3 case
    y(i) = f(i-1)
    end

    sum(y);

    -----

    Should work
     
  4. May 3, 2010 #3
    I got the following error for the same equation, following your summation of f(n),
    "??? Subscript indices must either be real positive integers or
    logicals.

    Error in ==> scriptrun at 16
    f(n)=sum(((abs((-1).^n))/((n+1./2).^(2))));"




    My code:

    for i=1:3 %n from 0 to 2 case
    f(n)=sum(((abs((-1).^n))/((n+1./2).^(2))));
    y(i)=f(i-1);
    end
    sum(y);
    uj = (-sig/Ha)*(xj-(((2*h)/(pi^2))*f(n)*sin((n+1/2)*((pi*xj)/h))*exp(((-Ha*ko)/(h^2))*((n+1/2)^2)*(pi^2)*t)));

    Any advise?
     
  5. May 3, 2010 #4
    You're summing uj = (-sig/Ha)*(xj-(((2*h)/(pi^2))*f(n)*sin((n+1/2)*((pi*xj)/h))*exp(((-Ha*ko)/(h^2))*((n+1/2)^2)*(pi^2)*t))) that's what f(n) is. just calling that expression will give an error, I believe.
     
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