牛頓法求解非線性方程組matlab源程序

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1、牛頓法求解非線性方程組matlab源程序Newton-Raphson求解非線性方程組matlab源程序matlab程序如下：function???hom[P,iter,err]=newton('f','JF',[7.8e-001;4.9e-001;3.7e-001],0.01,0.001,1000);disp(P);disp(iter);disp(err);?functionY=f(x,y,z)Y=[x^2+y^2+z^2-1;????2*x^2+y^2-4*z;????3*x^2-4*y+z^2];??functiony=JF(x,y,z)f1=

2、'x^2+y^2+z^2-1';f2='2*x^2+y^2-4*z';f3='3*x^2-4*y+z^2';df1x=diff(sym(f1),'x');df1y=diff(sym(f1),'y');df1z=diff(sym(f1),'z');df2x=diff(sym(f2),'x');df2y=diff(sym(f2),'y');df2z=diff(sym(f2),'z');df3x=diff(sym(f3),'x');df3y=diff(sym(f3),'y');df3z=diff(sym(f3),'z');j=[df1x,df1y,df1

3、z;df2x,df2y,df2z;df3x,df3y,df3z];y=(j);?function[P,iter,err]=newton(F,JF,P,tolp,tolfp,max)%輸入P為初始猜測值，輸出P則為近似解%JF為相應(yīng)的Jacobian矩陣%tolp為P的允許誤差%tolfp為f(P)的允許誤差%max：循環(huán)次數(shù)Y=f(F,P(1),P(2),P(3));fork=1:max????J=f(JF,P(1),P(2),P(3));????Q=P-inv(J)*Y;????Z=f(F,Q(1),Q(2),Q(3));????err=norm

4、(Q-P);????P=Q;????Y=Z;????iter=k;????if(err

5、

6、(abs(Y)

7、

8、abs(Y)<0.0001)????????break????endend?????function???homework4[P,iter,err]=newton('f','JF',[7.8e-001;4.9e-001;3.7e-001],0.01,0.001,1000);disp(P);disp(iter);disp(err);?func

9、tionY=f(x,y,z)Y=[x^2+y^2+z^2-1;????2*x^2+y^2-4*z;????3*x^2-4*y+z^2];??functiony=JF(x,y,z)f1='x^2+y^2+z^2-1';f2='2*x^2+y^2-4*z';f3='3*x^2-4*y+z^2';df1x=diff(sym(f1),'x');df1y=diff(sym(f1),'y');df1z=diff(sym(f1),'z');df2x=diff(sym(f2),'x');df2y=diff(sym(f2),'y');df2z=diff(sym(f2

10、),'z');df3x=diff(sym(f3),'x');df3y=diff(sym(f3),'y');df3z=diff(sym(f3),'z');j=[df1x,df1y,df1z;df2x,df2y,df2z;df3x,df3y,df3z];y=(j);?function[P,iter,err]=newton(F,JF,P,tolp,tolfp,max)%輸入P為初始猜測值，輸出P則為近似解%JF為相應(yīng)的Jacobian矩陣%tolp為P的允許誤差%tolfp為f(P)的允許誤差%max：循環(huán)次數(shù)Y=f(F,P(1),P(2),P(3));

11、fork=1:max????J=f(JF,P(1),P(2),P(3));????Q=P-inv(J)*Y;????Z=f(F,Q(1),Q(2),Q(3));????err=norm(Q-P);????P=Q;????Y=Z;????iter=k;????if(err

12、

13、(abs(Y)

14、

15、abs(Y)<0.0001)????????break????end