% 輸入數(shù)據(jù)

x=[-0.0003? ?? ???-0.0212? ?? ???-0.035? ?? ???-0.0474? ?? ???-0.0637? ?? ???-0.0755? ?? ???-0.0755? ?? ???-0.0814? ?? ???-0.0892? ?? ???-0.0964? ?? ???-0.0997? ?? ???-0.1121? ?? ???-0.1199? ?? ???-0.1467? ?? ???-0.1565? ?? ???-0.1611? ?? ???-0.1663? ?? ???-0.1729? ?? ???-0.1788? ?? ???-0.1833? ?? ???-0.1873? ?? ???-0.1931? ?? ???-0.1977? ?? ???-0.2023? ?? ???-0.2069? ?? ???-0.2134? ?? ???-0.2225? ?? ???-0.2317? ?? ???-0.2382? ?? ???-0.2454? ?? ???-0.2526? ?? ???-0.2578? ?? ???-0.2624? ?? ???-0.2676? ?? ???-0.2748? ?? ???-0.2846? ?? ???-0.2944? ?? ???-0.3016? ?? ???-0.3108? ?? ???-0.3219? ?? ???-0.333? ?? ???-0.3435? ?? ???-0.3539? ?? ???-0.3657? ?? ???-0.3735? ?? ???-0.3879? ?? ???-0.3997? ?? ???-0.4101? ?? ???-0.4193? ?? ???-0.4395? ?? ???-0.452? ?? ???-0.4592? ?? ???-0.469? ?? ???-0.4788? ?? ???-0.4912? ?? ???-0.4997? ?? ???-0.5095? ?? ???-0.5199? ?? ???-0.5324? ?? ???-0.5408? ?? ???-0.552? ?? ???-0.5598? ?? ???-0.5709? ?? ???-0.5794? ?? ???-0.5892? ?? ???-0.601? ?? ???-0.6121? ?? ???-0.6193? ?? ???-0.6284? ?? ???-0.635? ?? ???-0.6428? ?? ???-0.6546? ?? ???-0.6644? ?? ???-0.6716? ?? ???-0.6781? ?? ???-0.6729]';

y=[0.0007? ?? ???-0.0022? ?? ???-0.0036? ?? ???-0.0065? ?? ???-0.0109? ?? ???-0.0138? ?? ???-0.0138? ?? ???-0.0167? ?? ???-0.0196? ?? ???-0.0225? ?? ???-0.0255? ?? ???-0.0313? ?? ???-0.0356? ?? ???-0.0531? ?? ???-0.0589? ?? ???-0.0633? ?? ???-0.0662? ?? ???-0.0705? ?? ???-0.0735? ?? ???-0.0778? ?? ???-0.0807? ?? ???-0.0851? ?? ???-0.088? ?? ???-0.0924? ?? ???-0.0967? ?? ???-0.1025? ?? ???-0.1127? ?? ???-0.1215? ?? ???-0.1273? ?? ???-0.136? ?? ???-0.1418? ?? ???-0.1476? ?? ???-0.1535? ?? ???-0.1593? ?? ???-0.168? ?? ???-0.1767? ?? ???-0.1898? ?? ???-0.1985? ?? ???-0.2131? ?? ???-0.2262? ?? ???-0.2407? ?? ???-0.2538? ?? ???-0.2684? ?? ???-0.2829? ?? ???-0.2931? ?? ???-0.3149? ?? ???-0.3324? ?? ???-0.3455? ?? ???-0.36? ?? ???-0.3891? ?? ???-0.4065? ?? ???-0.4211? ?? ???-0.4371? ?? ???-0.4502? ?? ???-0.4705? ?? ???-0.4836? ?? ???-0.4996? ?? ???-0.5171? ?? ???-0.5389? ?? ???-0.552? ?? ???-0.5695? ?? ???-0.584? ?? ???-0.6015? ?? ???-0.6189? ?? ???-0.6364? ?? ???-0.6567? ?? ???-0.6756? ?? ???-0.6902? ?? ???-0.7033? ?? ???-0.7193? ?? ???-0.7324? ?? ???-0.7542? ?? ???-0.7716? ?? ???-0.7862? ?? ???-0.7964? ?? ???-0.7876]';

fx=@(b,x)(b(1)*x+b(2)*x.^3)./(1+b(3)*x+b(4)*x.^2); % 輸入模型

b=[0.14??48??-13.58??18.89]; %參數(shù)初值

for l=1:3??% 可隨b 的變化調(diào)節(jié)循環(huán)次數(shù)

b=lsqcurvefit(fx,b,x,y)

b=nlinfit(x,y,fx,b)

end

figure(1),clf

plot(x,y,'o','markersize',10,'markerfacecolor','b')

hold on

x1=min(x):range(x)/230:max(x);

y1=fx(b,x1);

plot(x1,y1,'r-','linewidth',3)

legend('data','fit','location','best')

nh82.jpg

(32.97 KB, 下載次數(shù): 5)

2011-9-8 15:52 上傳

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