Re: Use of fsolve

[Daniel Tourde]

Hello Mario,

> > I would like to use the fsolve solution for solving non-linear equations
> > where sometimes, solutions or constant are very small:
> 
> >   y(1) = 12*((x(3)*x(1))/2)/E - nlcoef(3);
> >   y(2) = 12*((x(3)*x(2)+x(1)*x(4))/6)/E - nlcoef(4);
> >   y(3) = 12*((P*x(3)/2+x(4)*x(2)+x(1)*x(5))/12)/E - nlcoef(5);
> >   y(4) = 12*((P*x(4)/2+x(5)*x(2))/20)/E - nlcoef(6);
> >   y(5) = 12*((P*x(5))/60)/E - nlcoef(7);
> 
> > Where some of my nlcoef values are very small (between 1e-7 and 1e-10).
> > It happens that the solutions given by fsolve can be wrong due to
> > rounding and precision errors.

 
> Perhaps you can get better values by rescaling the problem. 

Thanks for your answer. Yes it has answered my question and helped me to
solve my problem (at least I got answers with index 1).
 
> Are E and P also small?

No, around 1e5 for E and 50 for P 

 
> Hope this helps,

It has. Thanks


                        Daniel
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Daniel TOURDE                                   E-mail : address@hidden
The Aeronautical Research Institute of Sweden   Tel : +46 8 634 13 44
P.O. Box 11021 S-161 11 BROMMA, Sweden          Fax : +46 8  25 34 81
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