Hi!I have a problem with polyfit and polyval. I have two vectors (x and y). You can see it in the attached image (the red line). I want to create a polynom that allow to create the blue line (imagine that it doesn't exist) only with the values that I have.
I've tried with polyfit and polyfit but it doesn't work at all.
x2=x'; %I have changed the direction because if not, it doesn't do the polyfit.
coeffs1=polyfit(x2, msensiv_graf,1);coeffs3=polyfit(x2, msensiv_graf,3);coeffs5=polyfit(x2, msensiv_graf,5);coeffs12=polyfit(x2, msensiv_graf,12);new_y1 = polyval(coeffs1, x2);new_y3 = polyval(coeffs3, x2);new_y5 = polyval(coeffs5, x2);new_y12 = polyval(coeffs12, x2); plot(x2, msensiv_graf, 'r'); hold on plot(x2, new_y1, 'r'); plot(x2, new_y3, 'b'); plot(x2, new_y5, 'g'); plot(x2, new_y12, 'y');
And the error is:
Warning: Polynomial is badly conditioned. Add points with distinct X values, reduce the degree of the polynomial, or try centering and scaling as described in HELP POLYFIT.
Does somebody know what can I do? I also think to try interpolation to get the blue line.
Thanks a lot in advance.
Best Answer