Thank you Leo again. It works!!!
Best wishes, Marek.
_____________________
Leo Butler wrote:
>
>
> On Thu, 10 Jun 2010, Marek Pietrow wrote:
>
> < Sorry I am beginner. Could you write me if it is possible for maxima to find
> < coefficients of the curve, say, A+B*%e^(-C*x) from the list like
> < [[x1,y1],[x2,y2],...]? What method of fitting is possible?
> < Thank you. Marek Pietrow.
>
> See the lsquares package.
>
> Here is an example adapted from the help page:
>
> (%i1) load (lsquares)$
>
> /* generate artificial data */
> (%i2) M : genmatrix (lambda([x,y], if y=1 then x else
> .1*exp(-0.2*x)+2),10,2),numer;
>
> (%o2) matrix([1,2.081873075307798],[2,2.067032004603564],
> [3,2.054881163609402],[4,2.044932896411722],
> [5,2.036787944117144],[6,2.03011942119122],[7,2.024659696394161],
> [8,2.020189651799466],[9,2.016529888822159],
> [10,2.013533528323661])
>
> /* estimate the parameters: a=.1, b=-.2 c=2 */
> (%i3) lsquares_estimates (M, [x,y], y=a*exp(b*x)+c, [a,b,c],
> initial=[.2,.1,2], iprint=[-1,0]);
>
> (%o3) [[a = .1010185361658323,b = -0.184635888015087,c =
> 1.997155985989317]]
>
> Leo
>