deriving surface equation form data on a table
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i have a table with 3 variables(B/H)= 1,2,3,4,5,6,7,8 and fi= 0,10,20,30 and h which is depend on (B/H) and fi that contains 32 values. for example for fi=0 and (B/H)=1 >>h=1 fi=0 and (B/H)=2 >>h=1.02 ...... fi=30 and (B/H)=8 >>h=14800
>is there any way in MATLAB to get an surface equation for h in terms of (B/H) and fi??
h:[ 1 1.02 1.11 1.21 1.3 1.4 1.59 1.78
1 1.11 1.35 1.62 1.95 2.33 3.34 4.77
1.01 1.39 2.12 3.29 5.17 8.29 22 61
1.13 2.5 6.36 17.5 50 150 1400 14800 ]
4 个评论
Walter Roberson
2011-6-30
There are an infinite number of surface equations that would fit the data perfectly. Which one do you want?
milad babaei
2011-6-30
Sean de Wolski
2011-6-30
There can be at least one polynomial of order>(number elements) that fits perfectly. Thus from n-> infinity: To infinity and beyond!
milad babaei
2011-7-1
回答（1 个）
Andrei Bobrov
2011-6-30
BHv= [1,2,3,4,5,6,7,8];
fiv= [0,10,20,30];
h = rand(length(BHv),length(fiv))*30+10;
[fim BHm] = meshgrid(fiv,BHv);
[XI,YI] = meshgrid(linspace(fiv(1),fiv(end),100),linspace(BHv(1),BHv(end),100));
1 variant use 'interp2'
F1 = @(fi,BH)interp2(fim,BHm,h,fi,BH);
surf(F1(XI,YI))
2 variant use 'TriScatteredInterp'
F = TriScatteredInterp(fim(:),BHm(:),h(:));
figure,surf(F(XI,YI))
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2011-6-30
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