作业帮matlab 欧拉法程序错误程序：欧拉法：function [x,y] = eular_f (f,xint,yint,xfinal,n)h = (xfinal-xinit)/n;x = [xinit zeros(1,n)];y = [yinit zeros(1,n)];for i = 1:nx(i+1) = x(i)+h;y(i+1) = y(i)+h*f(x(i),y(i));endend改进的欧拉法：func
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![matlab 欧拉法程序错误程序：欧拉法：function [x,y] = eular_f (f,xint,yint,xfinal,n)h = (xfinal-xinit)/n;x = [xinit zeros(1,n)];y = [yinit zeros(1,n)];for i = 1:nx(i+1) = x(i)+h;y(i+1) = y(i)+h*f(x(i),y(i));endend改进的欧拉法：func](/uploads/image/z/3687734-38-4.jpg?t=matlab+%E6%AC%A7%E6%8B%89%E6%B3%95%E7%A8%8B%E5%BA%8F%E9%94%99%E8%AF%AF%E7%A8%8B%E5%BA%8F%EF%BC%9A%E6%AC%A7%E6%8B%89%E6%B3%95%EF%BC%9Afunction+%5Bx%2Cy%5D+%3D+eular_f+%28f%2Cxint%2Cyint%2Cxfinal%2Cn%29h+%3D+%28xfinal-xinit%29%2Fn%3Bx+%3D+%5Bxinit+zeros%281%2Cn%29%5D%3By+%3D+%5Byinit+zeros%281%2Cn%29%5D%3Bfor+i+%3D+1%3Anx%28i%2B1%29+%3D+x%28i%29%2Bh%3By%28i%2B1%29+%3D+y%28i%29%2Bh%2Af%28x%28i%29%2Cy%28i%29%29%3Bendend%E6%94%B9%E8%BF%9B%E7%9A%84%E6%AC%A7%E6%8B%89%E6%B3%95%EF%BC%9Afunc)
matlab 欧拉法程序错误程序：欧拉法：function [x,y] = eular_f (f,xint,yint,xfinal,n)h = (xfinal-xinit)/n;x = [xinit zeros(1,n)];y = [yinit zeros(1,n)];for i = 1:nx(i+1) = x(i)+h;y(i+1) = y(i)+h*f(x(i),y(i));endend改进的欧拉法：func
matlab 欧拉法
程序错误
程序：欧拉法：
function [x,y] = eular_f (f,xint,yint,xfinal,n)
h = (xfinal-xinit)/n;
x = [xinit zeros(1,n)];
y = [yinit zeros(1,n)];
for i = 1:n
x(i+1) = x(i)+h;
y(i+1) = y(i)+h*f(x(i),y(i));
end
end
改进的欧拉法：
function
[x,y] = eular_modified(f,xinit,yinit,xfinal,n)
h = (xfinal-xinit)/n;
x = [xinit zeros(1,n)];
y = [yinit zeros(1,n)];
for i = 1:n
x(i+1) = x(i)+h;
ynew = y(i)+h*f(x(i),y(i));
y(i+1) = y(i)+(h/2)*(f(x(i),y(i))+f(x(i+1),ynew));
end
end
在MATLAB的Editor中调用以上两个函数,输入：
f = @(x,y) 1/x^2-y/x;
g = @(x) (log(x)+1)/x;
xe = [1:0.05:2];
ye = g(xe);
%Call functions
[x1,y1] = eular_f(f,1,2,0.05,20);
[x2,y2] = eular_modified(f,1,2,0.05,20);
%Plot
plot(xe,ye,’k-’,x1,y1,’k-.’,x2,y2,’k:’)
xlabel(‘x’)
ylabel(‘y’)
legend(‘Analytical’,’Forward’,’Modified’)
axis([1 2 1 1])
%Estimate errors
error1 = [‘Forward
error.’
num2 str-100*(ye(end)-y1(end)/ye(end) ’%’)];
error2 = [‘Modified
error.’
num2 strl-100*lye(end)-yz(end)/ye(end) ’%’];
error = {error1,error2};
text(0.04,1.06,error)
结果显示?plot(xe,ye,’k-’,x1,y1,’k-.’,x2,y2,’k:’)
|
Error:Missing variable or function.
请问哪儿出错了,该怎么修改啊?
matlab 欧拉法程序错误程序：欧拉法：function [x,y] = eular_f (f,xint,yint,xfinal,n)h = (xfinal-xinit)/n;x = [xinit zeros(1,n)];y = [yinit zeros(1,n)];for i = 1:nx(i+1) = x(i)+h;y(i+1) = y(i)+h*f(x(i),y(i));endend改进的欧拉法：func
1/函数参数并不对应,函数内部的变量名与参数名不一致,看xinit与xinit,yinit与yinit
2/函数表达式有点小问题,g = @(x) (log(x)+1)/x;乘除的时候,是向量的话就应该换成点乘除
其他没有了