Resolving errors with Raphson method

3 次查看（过去 30 天）

Alexander 2023-9-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2022172-resolving-errors-with-raphson-method

评论： Star Strider 2023-9-17

Hello,

I am having difficulties in writing a Raphson method using a while loop. Matlab keeps returning error: y(0): "subscripts must be either integers 1 to (2^63)-1 or logicals". I have tried to change my code several times, to try to solve this problem, but I have been unsuccesful. I am wondering if anyone has any suggestions on how to solve this problem?

4 个评论
显示 2更早的评论隐藏 2更早的评论

Dyuman Joshi 2023-9-17

You have to loop over the values [1 2 3 ... length(x)], right? If yes, why not use a for loop? Because you are not breaking out of the while loop if a condition is met.

Also, I don't understand why you are adding x(i) to i, in the last line of the while loop.

Alexander 2023-9-17

Switched to a for loop and it works much better

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider 2023-9-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2022172-resolving-errors-with-raphson-method#answer_1312152

在 MATLAB Online 中打开

My pleasure!

The ‘y’ assignment needs to be an anonymous function, if I understand correctly what you want to do.

That change produces this result —

L = 1;

x = linspace(0,1,100);

y = @(x) (8*x)/(3*L) - 3*(x/L).^2 + (1/3)*(x/L).^3 - (2/3)*sin((pi*x)/L); % Anonymous Function

uy = 1/6*y(x);

figure

plot(x, y(x), 'DisplayName','y(x)')

hold on

plot(x, uy, 'DisplayName','uy(x)')

hold off

grid

xlabel('x')

ylabel('Function Values')

legend('Location','best')

See the documentation on Anonymous Functions for details. Call them as you would any other function. Similar to variables, they must be defined before they are used in the code they are implemented in.