blob: 8c1182a526a4c48bad900a69584a4b21b40ed87c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
function [x,y] = trapezoidal(x0,y0,xn,h,g)
//Trapezoidal method solving ODE
// dy/dx = g(x,y), with initial
//conditions y=y0 at x = x0. The
//solution is obtained for x = [x0:h:xn]
//and returned in y
ymaxAllowed = 1e+100
x = [x0:h:xn];
y = zeros(x);
n = length(y);
y(1) = y0;
for j = 1:n-1
y(j+1) = y(j) + h*(g(x(j),y(j))+g(x(j+1),y(j+1)))/2;
if y(j+1) > ymaxAllowed then
disp('Euler 1 - WARNING: underflow or overflow');
disp('Solution sought in the following range:');
disp([x0 h xn]);
disp('Solution evaluated in the following range:');
disp([x0 h x(j)]);
n = j;
x = x(1,1:n); y = y(1,1:n);
break;
end;
end;
endfunction
//End function trapezoidal
|
