[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: leasqr problem

From: Jordi Gutiérrez Hermoso
Subject: Re: leasqr problem
Date: Sun, 25 Jan 2009 23:22:42 -0600

2009/1/24 Jose Rodriguez <address@hidden>:
> I'm trying to solve a problem with leasqr, where the observed
> value, instead of being a set of points y=f(x), is the result of a
> definite integral. I found that I can use leasqr if I adjust the
> dimensions of the function to fit and its expected values to the
> dimension of the x range:

Hi, I think you're a little muddled about how you're approaching the
problem here.

First of all, the x's aren't observation points. In fact, x doesn't
"exist", because it's a bound variable. :-)

You are trying to solve the overdetermined system

     F(a) = 0.5
     G(a) = 1

where F(a) and G(a) are your two integrals, you only have one
observation point, the vector [0.5;1]. So the best you can do is try
to find the a s.t. the norm of [F(a); G(a)] - [0.5; 1] is minimal.

In this case it's not so hard to just search. Try plotting [F(a),G(a)]
as a parametric function of a. If I didn't make a mistake, it looks
vaguely like a parabola, and you are looking for the a that gives you
the point on this parabola that is closest to the point (0.5,1).

I hope I understood your problem correctly,
- Jordi G. H.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]