Re: Programming problems

Nita DRAGOE ( tdragoe@hongo.ecc.u-tokyo.ac.jp )
Fri, 18 Jul 1997 09:02:47 +0900

Manuel J. Roman Alpiste wrote:

> I'm making a X-Ray diffraction analysis program but I've got a little
> problem. I need a good function to find the maximun intensity point of a
> peak in a diagram. I must use the second derivate to calculate this point
> but I don't know an effective function to make this.
>

Finding the peak is based on the derivatives. You can use a local
interpolation function. A classic method is based on polynomials
but be aware of the Runge phenomena, don't raise the
polynomial degree.
In some software I made, I use a method which is called the
pseudo-inverse
matrix, which can find a pseudo-solution of an over-determined system
(you can
find the description in any numerical methods book).

N. Dragoe

-- << If all men are created equal, why don't we all weigh the same? >>
--Dr. Nita DRAGOEDepartment of Applied ChemistryFaculty of Engineering, University of Tokyo7-3-1 Hongo, Bunkyo-ku, Tokyo, JAPANTel: 81-3- 3812 2111 (ext. 7202)Fax: 81-3- 3815 5632

http://www.hongo.ecc.u-tokyo.ac.jp/~tdragoe/personal.htm