Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Surface fitting problem

Surface fitting problem

Surface fitting problem

Hi have problem when doing surface fitting the surface that i obtained has the x and y axis switched. The code is:

 ft = fittype( 'poly33' );
    opts = fitoptions( ft );
    opts.Weights = zeros(1,0);
    coeffnames(ft)  %mostra os coeficientes
    formula(ft)   %mostra a equação final
    c = fit( [xi, yi], zi, ft, opts )
    coef = coeffvalues(c)
    figure( 'Name', 'Surface fitting' );
    h=plot( c, [xi, yi], zi );

And when i going to cheek the surface it apperes that x and y are exchanged.

    for i=1:50+1

    clear x y
    for i=1:50+1
        for j=1:50+1
    Z(i,j)=coef(1,1) + coef(1,2)*x + coef(1,3)*y + coef(1,4)*x^2 + coef(1,5)*x*y + coef(1,6)*y^2 + ...
        coef(1,7)*x^3 + coef(1,8)*y*x^2  + coef(1,9)*x*y^2 + coef(1,10)*y^3;


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close