Origin Ver. and Service Release (Select Help-->About Origin): 7.5
Operating System: XP2 prof
Hi,
I have a rather strange problem.
I need to make an integral over a rather stiff funcyion of a parameter, lets say, x.
Its on the form:
y = int exp (exp(-arg(x))dx
Strangly Origin is not able to find the minima using the Marquard-Lewenberg routine but using Simplex it does. That might be related to the problem with calculations of the the derivatives and steep minima.
So far I can accept this- but the problem is that when I calculate/generate the function after seeing that the fited line coinicides withe the exp data, the calculated curves is completely off. In other words the fitted line is OK, but saying "Done" the curve turns completely different!!
I have used a simple summation to calculate the integral, but varying the step, range do not influence anything. (By the way where are the descriptions on how to use the NAG routines to do various integrals?)
Can you please helpe me?
thanks a lot in advance. |
Simplex/ML fitting rout and numerical integrations
Posted - 10/23/2009 : 09:53:47 AM
