Error message "Functions definitions are not permitted in this context" Hey guys, I'm trying to build a code to calculate a polynomial using Newton's divided method, but every time I enter a code, even the one in the book , I get this error message.

CODE #1:

function F = div_diff(x, y)
% div_diff function computes all divided differences for 
%  the data stored in x and y = f(x)
n = length(x);
m = length(y);
if m~=n; error('x and y must be same size');
else
    F = zeros(n, n);
    for i = 1:n  % define 0th divided difference
        F(i,1) = y(i);
    end
    for k = 1:n-1   % Get kth divided difference
        for i = 1:n-k
            F(i,k+1) = (F(i+1,k)-F(i,k))/(x(i+k)-x(i));
        end
    end

      x=[1970,1990];
      y=[3707475887,5281653820];
      div_diff(x,y)

Code#2 from the Book(Timothy Sauer Numerical Analysis)

%Input: x and y are vectors containing the x and y coordinates 
% of the n data points
%Output: coefficients c of interpolating polynomial in nested form
%Use with nest.m to evaluate interpolating polynomial
 function c=newtdd(x,y,n)
for j=1:n
  v(j,1)=y(j);        % Fill in y column of Newton triangle
end
for i=2:n             % For column i,
  for j=1:n+1-i       % fill in column from top to bottom
    v(j,i)=(v(j+1,i-1)-v(j,i-1))/(x(j+i-1)-x(j));
  end
end
for i=1:n
  c(i)=v(1,i);        % Read along top of triangle
end                   % for output coefficients

x0=[1970,1990];
y0=[37007475887,5281653820];
c=newtdd(x0,y0,2);
x=0:.01:5281653820;
y=nest(1,c,x,x0);

Answer 1

[Image Analyst]

Please attach the m-file(s). You probably put these functions into a script or something like that. Or possibly you're missing an end statement or parenthesis or something. You did not include the full error message (ALL the red text) so I'm just guessing at the moment.

[Gervais]

>> function F = div_diff(x, y) % div_diff function computes all divided differences for % the data stored in x and y = f(x) n = length(x); m = length(y); if m~=n; error('x and y must be same size'); else F = zeros(n, n); for i = 1:n % define 0th divided difference F(i,1) = y(i); end for k = 1:n-1 % Get kth divided difference for i = 1:n-k F(i,k+1) = (F(i+1,k)-F(i,k))/(x(i+k)-x(i)); end end

    x=[1970,1990];
    y=[3707475887,5281653820];
    div_diff(x,y)

 function F = div_diff(x, y)
|
Error: Function definitions are not permitted in this context.