数学建模社区-数学中国
标题:
灰色模型
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作者:
zhang6880258
时间:
2012-6-28 00:09
标题:
灰色模型
我在matlab中用GM（1,1）模型预测，可是误差太大了。请高手指点~~~~~~~~~~
clear
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syms a b;
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c=[a b]';
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A=[539.658590944408,544.467335019023,543.118901615168,541.395536784412,539.719603563031,538.320685053971,536.799895148485,539.869612431029,534.915223499512,544.533125668254];
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B=cumsum(A);
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n=length(A);
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for m=1:(n-1)
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C(m)=(B(m)+B(m+1))/2;
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end
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D=A;
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D(1)=[];
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D=D';
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E=[-C;ones(1,n-1)];
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c=inv(E*E')*E*D;
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c=c';
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a=c(1);
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b=c(2);
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F=[];
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F(1)=A(1);
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for m=2:(n+10)
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F(m)=(A(1)-b/a)/exp(a*(m-1))+b/a;
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end
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G=[];
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G(1)=A(1);
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for m=2:(n+2)
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G(m)=F(m)-F(m-1);
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end
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t1=1:10;
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t2=1:12;
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plot(t1,A,'r',t2,G,'g')
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复制代码
作者:
wssl103050
时间:
2012-6-28 10:59
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