|Jun4-12, 10:57 AM||#1|
Global Errors when solving the Equation of Motion
I’m implementing a code to solve the equation of motion using the 4-step Adams-Bashforth method.
Here’s my section of code that does this:
upnew= up + delta *( (55/24)*a - (59/24)*am1 +(37/24)*am2 - (3/8)*am3 );
xnew=x + delta *( (55/24)*up - (59/24)*upm1 +(37/24)*upm2 - (3/8)*upm3);
It seems to work; at least it produces sensible results which agree with the Euler forwards method. However, I read that the global error should be proportional to delta^4, but this code produces results that have errors proportional to delta. Why is this? Is there some quirk of using the method as a double integral reduces the accuracy? Or am I getting something wrong?
Thanks in advance,
|Jun4-12, 12:09 PM||#2|
The fix is to update things in the right order.
and similarly for the u's
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