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## 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.