改进平方根.m

matlab中运用Simpson求积时的求积函数

function x=msqroot(A,b,n)
for j=1:n
    for i=1:j-1
        v(i)=A(j,i)*A(i,i);
    end
    for t=1:j-1
        A(j,j)=A(j,j)-A(j,t)*v(t);
    end
    for r=j+1:n
        K=0;
        for s=1:j-1
            K=K+A(r,s)*v(s);
        end
        A(r,j)=(A(r,j)-K)/A(j,j);
    end
end
%生成L
for i=1:n
    for j=1:n
        if j>i L(i,j)=0;
        elseif j==i L(i,j)=1;
        elseif j<i L(i,j)=A(i,j);
        end
    end
end
%生成D
for i=1:n
    for j=1:n
        D(i,j)=0;
    end
end
for i=1:n
    D(i,i)=A(i,i);
end
%生成U
U=D*L';
%运用前代法求解LY=b,Y用b储存
b=qiandai(L,b,n);
%运用回代法求解UX=b,X用b储存
b=huidai(U,b,n);
%在命令窗口输出问题的解
x=b;
end